TRANSMISSION 
LINE  CONSTRUCTION 


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TRANSMISSION    LINE 
CONSTRUCTION 

METHODS  AND  COSTS 


BY 

R.  A.  LUNDQUIST,  E.  E. 

CONSULTING  ENGINEER 


McGRAW-HILL   BOOK  COMPANY 

239  WEST  39TH  STREET,  NEW  YORK 

6  BOUVERIE  STREET,  LONDON,  E.  C. 

1912 


COPYRIGHT,  1912,  BY  THE 
MCGRAW-HILL  BOOK  COMPANY 


THE. MAPLE. PRESS. YORK. PA 


PREFACE 

There  is,  at  present,  no  book  treating  adequately  of  the 
practical  methods  employed  in  modern  high-tension  line  construc- 
tion. The  writer's  aim  in  this  book  has  been  to  supply  material 
of  value  to  the  man  actively  engaged  in  this  kind  of  work,  and 
to  set  forth  the  respective  merits  of  the  various  types  of  line 
construction,  together  with  the  methods  commonly  employed 
in  their  building.  No  attempt  has  been  made  to  cover  the 
electrical  and  mechanical  calculations  involved.  The  book 
treats  the  subject  from  the  standpoint  of  the  construction  man 
rather  than  that  of  the  office  engineer. 

Considerable  attention  has  been  given  to  cost  data.  In 
handling  this  material,  the  aim  has  been  to  note  as  far  as  possible 
all  conditions  which  might  affect  costs,  and  to  make  these  data 
as  definite,  useful  and  reliable  as  possible. 

The  writer  wishes  to  acknowledge  the  assistance  of  Mr.  E.  J. 
Le  Blond,  Minneapolis,  Minn.,  Mr.  W.  K.  Archbold,  President 
of  the  Archbold-Brady  Co.,  Syracuse,  N.  Y.,  and  Mr.  Charles 
E.  Brooks,  Minneapolis,  Minn.,  in  securing  much  valuable 
information. 

He  also  desires  to  express  his  appreciation  of  illustrative  matter 
provided  by  the  Locke  Insulator  Mfg.  Co.,  The  Ohio  Brass  Co., 
The  Archbold-Brady  Co.,  the  Electrical  World,  the  Franklin 
Steel  Co.,  the  Bowie  Switch  Co.,  the  Pacific  Elec.  &  Mfg.  Co., 
the  Railway  &  Industrial  Eng.  Co.,  W.  N.  Matthews  &  Bro., 
and  others. 

R.  A.  LUNDQUIST. 
MINNEAPOLIS,  MINN., 
July,  1912. 


263610 


CONTENTS 


PAGE 
PREFACE  v 

CHAPTER  I 
PRELIMINARY  WORK 1 

CHAPTER  II 

LOCATION  OF  LINE — SURVEYS  AND  ENGINEERING 11 

CHAPTER  III 
TYPES  OF  CONSTRUCTION 25 

CHAPTER  IV 

WOODEN  POLE  CONSTRUCTION 55 

CHAPTER  V 

STEEL  POLE  CONSTRUCTION      89 

CHAPTER  VI 

STEEL  TOWER  CONSTRUCTION 103 

CHAPTER  VII 
REINFORCED  CONCRETE  CONSTRUCTION 135 

CHAPTER  VIII 
SPECIAL  STRUCTURES 156 

CHAPTER  IX 
CROSS-ARMS,  HARDWARE,  PINS  AND  INSULATORS 184 

CHAPTER  X 
GUYING 209 

CHAPTER  XI 
STRINGING  WIRE 230 

CHAPTER  XII 

COST  DATA  OF  TYPICAL  TRANSMISSION  LINES 253 

vii 


viii  CONTENTS 

CHAPTER  XIII 

OHGANIZATION  AND  TOOLS 262 

APPENDIX  A 272 

APPENDIX  B 273 

APPENDIX  C 276 

APPENDIX  D 279 

APPENDIX  E 281 

APPENDIX  F 285 

INDEX  .  287 


TRANSMISSION  LINE  CONSTRUCTION 
METHODS  AND  COSTS 

CHAPTER  I 
PRELIMINARY  WORK 

In  this  discussion  of  the  engineering  methods  employed  in  the 
laying  out  and  building  of  a  transmission  line,  it  is  assumed  that 
the  work  is  of  sufficient  magnitude  to  warrant  the  study  and 
investigations  to  be  described;  where  work  of  lesser  importance 
is  to  be  carried  out,  the  point  to  which  the  same  procedure  can  be 
applied  economically  must  be  left  to  the  judgment  of  the  engineer. 
From  the  writer's  personal  observations,  however,  he  is  led  to 
believe  that  in  most  cases  not  enough  rather  than  too  much  atten- 
tion is  given  to  details  in  the  engineering  of  transmission  lines. 

The  first  step  preparatory  to  the  construction  of  any  kind  of 
a  line  is  the  making  of  a  general  map.  The  main  points  between 
which  the  line  is  to  be  built  will  have  already  been  determined 
upon  and  the  map  of  the  intervening  territory  should  now  be  laid 
out  to  such  a  scale  that  it  will  be  convenient  to  handle  in 
making  the  preliminary  investigations  in  the  field,  but  still  be 
large  enough  to  show  clearly  for  office  study,  all  division  lines, 
towns,  villages,  roads,  streams,  railroads,  bridges,  etc.;  and  to 
allow  for  the  laying  out  on  it  with  accuracy,  of  all  existing 
telephone,  telegraph  and  transmission  lines.  The  territory  to 
be  included  in  this  general  map  will  necessarily  be  determined 
by  the  possible  diversity  of  the  lines  and  the  judgment  of 
the  engineer,  based  upon  his  knowledge  of  conditions.  In  the 
making  of  it,  county  plat  books  will  be  found  very  useful  and 
though  such  books  are  not  generally  very  accurate  as  to  recent 
changes  in  roads,  etc.,  they  will  be  sufficiently  so  for  all  pre- 
liminary work.  Discrepancies  can  be  noted  as  this  work  pro- 
gresses, and  changes  can  be  made  accordingly. 

In  addition  to  the  map  just  described,  topographic  maps  or 
atlas  sheets,  as  published  by  the  United  States  Geological  Survey, 
should  be  secured  if  they  are  available  for  the  section  of  the 

1 


2  '  TRANSMISSION  LINE  CONSTRUCTION 

country  to  be  traversed.  These  atlas  sheets,  about  16  1  /  2  in.  X  20 
in.,  usually  taking  in  quadrangles  of  7  1/2  or  15  minutes  of  latitude 
and  longitude  on  a  side,  give  contour  lines,  bench  marks  and  many 
reference  points  and  details  that  will  help  greatly  in  studying  the 
topography  of  any  section  of  the  country.  As  yet,  however, 
only  a  small  percentage  of  the  area  of  the  states  has  been  mapped 
in  this  way,  so  that  it  may  not  be  possible  to  obtain  them;  in 
that  event,  much  information  can  be  gleaned  by  a  careful  study 
of  the  courses  of  streams  and  the  lay  of  roads  on  the  general  map. 
While,  of  course,  relative  elevations  cannot  be  determined  to  any 
extent,  the  rough  and  hilly  sections  will  be  easily  located  and  other 
general  knowledge  of  the  topography  of  the  country  secured. 

As  he  studies  the  geographical  features  of  the  territory  and 
familiarizes  himself  with  the  general  lay  of  the  land,  the  engineer 
should  also  look  into  the  statistics  of  the  towns  and  villages 
throughout  the  country  traversed,  noting  their  population, 
wealth,  industrial  plants,  existing  light  and  power  plants,  electric 
railways,  shipping  facilities,  future  prospects,  and  all  other  points 
that  will  determine  whether  any  business  might  later  on  be  de- 
veloped in  them  that  would  have  a  bearing  on  the  location  of  the 
line.  It  very  often  happens  that  cases  are  noted  where  lines 
of  moderate  capacity  and  voltage  have  been  built  merely  as  a 
connection  between  two  points  in  total  disregard  of  all  possible 
opportunities  for  load  that  might  be  developed  at  any  of  the 
small  villages  in  the  country  passed  through,  where  not  only 
would  the  average  revenue  per  kilowatt-hour  be  much  higher, 
but  the  conditions  for  continuity  of  service  would  not  be  so 
exacting.  Against  this,  the  argument  is  made  that  under  these 
conditions  the  construction  costs  and  operating  charges  are  too 
high  for  small  high-voltage  plants,  that  the  growth  is  limited 
and  that  it  involves  risks  to  the  service,  in  that  trouble  in  any  one 
of  the  smaller  sub-stations  or  lines  connecting  them  to  the  main 
line  will  interrupt  the  service  of  the  heavier  customers  on  the 
trunk  lines  direct.  This  argument  may  be  true  if  the  proper 
arrangements,  now  usually  not  considered  difficult,  be  not  made; 
but  with  modern  well-tried  high-voltage  apparatus,  proper 
segregation  of  trouble  can  ordinarily  be  made  automatically 
with  very  little  voltage  disturbance. 

The  possibilities  for  revenue  from  small  communities  in  the 
territory  to  be  traversed  should  certainly  be  considered,  especially 
in  the  case  of  moderate  capacity  lines;  and,  profiting  by  the 


PRELIMINARY  WORK  3 

experience  of  the  past,  these  possibilities  are  beginning  to  be 
noted  even  to  the  degree  of  extending  lines  from  large  central 
steam  stations. 

In  studying  the  towns  and  villages,  note  should  be  made  of  the 
roads  radiating  from  them  and  their  general  lay.  This  informa- 
tion will  be  of  great  value  in  determining  the  accessibility  for 
construction  and  maintenance  of  the  different  tentative  routes 
laid  out  in  the  preliminary  study.  Then  taking  into  considera- 
tion with  his  geographical  and  statistical  data  as  noted  in  the 
foregoing,  the  possible  use  of  the  public  highways  or  the  parallel- 
ing of  them,  the  following  of  section  lines  or  the  right-of-way 
of  a  railroad,  as  discussed  below,  the  engineer  is  prepared  to 
sketch  in  tentative  routes  on  his  maps  for  further  study  in  the  field. 

Naturally,  from  the  standpoint  of  first  cost,  he  must  work  to 
secure  the  shortest  line  practicable,  but  he  must  also  consider  the 
probable  right-of-way  costs,  and  from  the  latter  angle  alone,  he 
will  often  discover  that  "the  shortest  way  across  is  the  longest 
way  around,"  and  that  he  can  well  afford  to  make  detours  and 
avail  himself  of  roads,  section  lines,  etc.  The  paralleling  of 
highways,  or  the  use  of  them  where  not  already  occupied  by 
heavy  telephone  leads,  results  in  a  transmission  line  that  is 
very  accessible  both  for  construction  and  maintenance,  and 
that  naturally  lends  itself  to  the  quick  location  of  cases  of  line 
trouble.  A  point  advanced  against  the  use  of  highways  for 
high-tension  lines  is  that  they  are  liable  to  damage  from  external 
influences.  However,  it  has  been  the  writer's  experience  that 
when  high-tension  lines  are  located  along  a  road  where  there  are 
even  a  few  scattered  farm-houses,  the  fear  of  detection  usually 
deters  persons  from  attempting  to  bring  injury  to  the  line. 
While  on  the  subject,  it  may  be  well  to  state  that  the  best  insur- 
ance against  anything  of  this  nature  is  for  the  company  to  adhere 
strictly  to  a  policy  of  absolute  fair  dealing  in  all  its  right-of-way 
and  damage  transactions,  not  striving  to  drive  too  sharp  a 
bargain,  and  thus  avoid  all  possibilities  of  incurring  the  enmity 
of  its  neighbors  along  the  line.  Cultivating  the  acquaintance 
of  these  people  pays  well  in  the  good  will  they  will  evidence 
toward  the  company  at  all  times,  and  the  friendly  assistance  that 
they  will  render  in  times  of  trouble  on  the  line. 

With  his  maps  and  data  the  engineer  is  now  prepared  to  make 
a  reconnaissance  of  the  routes  he  has  laid  out  on  paper,  driving 
or  riding  through  the  country.  He  will  note  the  general  character 


4  TRANSMISSION  LINE  CONSTRUCTION 

of  the  land  and-its  soil,  the  streams  and  their  banks  at  points  of 
crossing,  ravines  and  erosions,  timber,  exposed  slopes  and  ridges, 
houses  and  buildings  near  by,  all  telegraph,  telephone  and  trans- 
mission lines  and  railroads  with  the  possible  methods  of  making 
crossings.  His  investigations  should  be  electrical  as  well  as 
mechanical.  He  should  be  on  the  lookout  for  evidences  of  pre- 
valent lightning  conditions  in  the  shape  of  blasted  trees  or  split 
telegraph  and  telephone  poles.  In  connection  with  the  last 
point,  interviews  with  the  repairmen  and  "trouble  shooters"  of 
companies  who  are  operating  lines  in  that  vicinity  will  be  of  great 
value  in  determining  the  zones  subject  to  severe  lightning  dis- 
turbances. Where  it  is  proposed  to  utilize  the  highways  if 
feasible,  careful  note  should  be  made  of  all  shade  trees  which 
would  interfere  with  the  line,  with  special  reference  as  to  height 
and  kind,  number  and  location,  distance  from  house  or  buildings, 
with  names  of  owners.  As  a  rule,  shade  trees  involve  much 
expense,  not  always  on  account  of  their  intrinsic  value,  but  of 
the  sentiment  attached  to  them.  Very  frequently  it  is  hard  to 
secure  proper  trimming  clearance  at  any  price.  Then  again, 
trees  like  cottonwood  and  poplar  with  their  easily  breaking 
branches  are  often  of  such  height  that  it  is  necessary  to  pur- 
chase the  right  of  cutting  or  trimming  them  when  they  are  at  a 
comparatively  great  distance  from  the  line. 

Where  the  line  is  to  pass  through  well-settled  country  with 
rich  farms  and  prosperous-looking  homes,  it  is  a  wise  policy,  in 
addition  to  utilizing  roads  where  available  or  paralleling  them, 
to  seek  a  route  that  will  follow  natural  division  lines  of  the  land, 
such  as  section  lines,  as  far  as  possible.  Under  these  conditions 
the  right-of-way  for  a  line  of  poles  or  towers,  especially  the 
former,  will  be  very  much  cheaper  and  more  easily  secured. 
A  line  of  poles  set  closely  into  a  fence,  and  one  usually  finds  fences 
along  section  lines,  will  not  materially  interfere  with  the  working 
of  the  land.  It  is  likewise  apparent  that  a  line  of  towers  which 
parallels  closely  the  line  fence  of  a  field  will  not  prove  the  incon- 
venience or  effect  the  permanent  injury  to  it,  that  a  line  which 
runs  through  the  middle  of  the  field  will.  This  will  apply 
whether  the  right-of-way  is  secured  by  title  or  by  easement.  In 
the  latter  case  where  only  the  right  to  the  tower  location  is  in- 
cluded, with  rights  of  access  when  needed,  and  the  towers  are 
located  in  a  field  of  growing  grain,  it  is  obvious  that  every  time  a 
patrolman  finds  it  necessary  to  go  closely  up  to  a  structure  so 


PRELIMINARY  WORK  5 

situated,  it  makes  a  vast  difference  to  the  owner  whether  the 
tower  is  in  the  middle  or  at  the  edge  of  his  field.  To  appreciate 
these  points  thoroughly,  one  has  only  to  spend  a  little  time  with 
the  right-of-way  men  at  their  work. 

Having  covered  the  country  thoroughly  and  studied  the 
conditions  met  with  along  his  various  tentative  routes,  the 
engineer  can  lay  out  a  preliminary  line  that  will  fulfill  conditions 
most  satisfactorily.  In  general,  these  conditions  are  that  the 
line  should  be  as  direct  as  possible  with  due  consideration  to 
possibilities  for  load  in  the  territory  between  its  terminals; 
that  it  should  avoid  as  much  as  practicable  the  crossing  of 
isolated  hills  and  ridges,  swamps  and  bottom  lands  and  to 
lessen  its  exposure  to  storm  as  noted  in  practice,  it  should  also 
avoid  western  slopes;  that  it  should  skirt  around  sections  known 
to  be  subject  to  severe  lightning;  that  as  far  as  is  practicable,  it 
should  avail  itself  within  the  limits  of  sound  construction  of  the 
cheaper  right-of-way,  of  natural  division  lines  of  the  land  and  of 
public  highways,  and  that  it  should  be  of  the  greatest  possible 
accessibility  for  construction  and  maintenance.  Naturally, 
many  of  these  conditions  are  antagonistic,  as  met  with  in  any 
engineering  work,  and  the  choice  rests  upon  the  knowledge  and 
experience  of  the  engineer,  and  his  preliminary  line  as  laid  out  on 
the  map  should  be  the  result  of  careful  consideration  and  study 
of  the  various  conflicting  conditions.  With  the  paper  location 
of  the  proposed  route  completed,  a  thorough  investigation  of  it 
should  be  made  either,  if  in  rough  country  and  the  importance 
of  the  line  warrants  it,  by  a  stadia  survey  or  merely  by  the 
engineers  liding  or  walking  over  the  ground  in  territory  where 
it  is  possible  to  pick  up  landmarks  and  follow  the  paper  location 
closely  in  the  field.  Of  course,  this  is  very  easily  done  in  well- 
settled  country,  but  it  is  another  matter  where  the  roads  are 
practically  nothing  but  trails  and  are  changed  at  the  whim  of 
travelers. 

Where  a  survey  is  to  be  made,  a  party  of  two  or  three  equipped 
with  a  stadia  instrument  and  a  14-ft.  stadia  board  will  handle 
the  work  readily,  excepting  where  thick  underbrush  or  much 
timber  is  encountered,  where  it  will  be  found  good  economy  to 
hire  an  axeman.  Ordinarily  a  crew  of  the  foregoing  size  will 
make  a  survey  of  this  character  and  get  all  the  data  necessary 
for  transmission  line  work  at  a  cost  of  from  $5  to  $10  per  mile.  It 
should  run  1  mile  to  4  miles  a  day,  depending  upon  the  character 


6  TRANSMISSION  LINE  CONSTRUCTION 

and  topography  of  the  country.  The  surveying  party  should 
be  carefully  instructed  by  the  engineer  as  to  data  to  be  secured, 
and  the  work  should  be  carried  out  under  his  general  supervision. 
In  addition  to  the  line  and  levels,  the  crew  should  make  detailed 
notes  of  the  topography,  describing  the  character  of  the  ground, 
kind  and  size  of  timber,  slopes,  all  swamps,  streams  and  bottom 
land  closely  contiguous  to  the  proposed  line  as  well  as  actually 
on  it,  noting  generally  the  character  of  the  country  for  a  short 
distance  on  either  side  of  the  line  of  survey,  and  they  should 
describe,  illustrating  with  sketches,  all  highway,  river,  telegraph, 
telephone,  transmission  line  and  railroad  crossings  that  are  to  be 
made,  noting  for  the  lines,  the  spans,  height  of  poles,  number  of 
wires  carried,  etc.,  with  possible  locations  and  foundations  for 
the  proposed  line  structures. 

These  refinements  are  not  generally  observed  in  average  line 
work  and  are  often  scoffed  at.  Yet  they  require  little  additional 
time  and  are  very  valuable  in  deciding  upon  the  type  of  con- 
struction best  suited  to  conditions  and  in  preparing  estimates 
therefor;  furthermore,  if  it  should  be  necessary  on  account  of 
right-of-way  difficulties,  etc.,  to  make  any  slight  changes  in  the 
line,  sufficient  data  are  available  to  determine  upon  their  feasi- 
bility without  the  necessity  of  a  special  trip  to  the  spot.  From 
the  notes  and  data  of  the  survey  a  profile  is  prepared;  the  prepa- 
ration and  use  of  this  is  described  in  the  next  chapter.  Where 
an  instrument  survey  is  deemed  unnecessary,  the  engineer  or  an 
assistant,  by  walking  over  the  line  and  making  detailed  notes  as 
previously  outlined,  can  make  a  study  of  the  route  which  will  be 
sufficient  for  all  practical  purposes. 

As  he  is  now  provided  with  all  the  necessary  field  data  to 
supplement  his  statistical  information,  including  probable 
right-of-way  costs  for  pole  and  tower  construction,  secured  by 
investigation  of  land  values  and  by  inquiry  among  representative 
farmers,  the  engineer  is  prepared  to  decide  upon  the  type  of 
construction  that  is  best--  suited  to  the  conditions.  He  has 
available,  wood,  steel  and,  with  limitations,  concrete  poles  and 
steel  towers  and  while,  under  existing  financial  conditions,  it 
has  often  happened  that  steel  construction  has  never  been  con- 
sidered owing  to  its  repute  for  high  first  cost,  there  has  been 
in  recent  years  a  decided  change  in  sentiment,  especially  with 
companies  that  have  used  both  steel  and  wood,  and  that  have 
found  that  the  lower  priced  labor  which  is  possible  with  steel 


PRELIMINARY  WORK  7 

construction  frequently  makes  the  cost  per  mile  of  the  completed 
steel  tower  line  compare  very  favorably  with  that  of  wood.  In 
some  instances,  the  cost  of  a  steel  line  has  actually  been  less  than 
that  of  wood.  Of  course,  this  condition  is  more  true  in  the 
higher  voltages  but  with  the  semi-flexible  systems  and  the 
patented  types  of  poles  which  are  now  being  used  to  an  increasing 
extent,  it  is  often  possible,  even  in  the  lower  voltages,  to  obtain 
a  first  cost  equal  to  that  of  wooden  construction. 

It  is  apparent,  therefore,  that  all  practicable  forms  of  con- 
struction should  be  considered  and  estimates  made  df  the  cost 
under  the  conditions  existing.  This  is  another  point  that,  queer 
as  it  may  seem,  is  frequently  overlooked.  We  have  estimates 
made  up  of  the  comparative  costs  of  different  types  of  construc- 
tion where  no  attempt  is  made  to  ascertain  local  conditions  and 
their  relative  influence  on  the  construction  costs  of  these  different 
types.  Only  the  costs  of  material  at  the  given  point  are  in- 
vestigated, and  the  labor  items  assumed  on  an  equal  basis.  The 
fallacy  of  such  a  method  of  preparing  estimates  for  comparison 
is  clearly  apparent  when  we  take  actual  relative  labor  costs  of, 
say,  wooden  pole  and  steel  tower  construction  on  good  dry 
ground  and  compare  them  with  those  for  the  same  types  in  soft 
bottom  land.  In  the  latter  case,  the  poles  can  often  be  "worked 
in"  at  only  little  more  than  the  cost  of  setting  in  dry  ground, 
whereas  extensive  cribbing  or  sheathing  must  be  employed  to 
permit  the  proper  setting  of  the  tower  anchors,  thus  necessitating 
a  great  increase  over  normal  for  this  part  of  the  work.  The  as- 
sembling and  erection  costs  would  also  be  greater  under  the 
latter  conditions. 

With  his  knowledge  of  the  route  and  any  possible  changes  that 
might  be  made  to  the  advantage  of  one  type  of  construction  or 
another,  of  the  varying  influences  of  local  conditions  on  the  labor 
costs,  of  the  probable  costs  of  right-of-way  per  pole  or  tower  for 
the  different  types,  of  the  transportation,  of  field  expenses,  etc., 
in  addition  to  his  data  regarding  the  material  required,  the 
conditions  of  voltage,  size  of  conductors,  number  of  circuits, 
necessary  heights  of  poles  and  towers,  spans,  etc.,  imposed,  the 
engineer  will  be  able  to  prepare  comparative  estimates  of  first 
cost  for  the  different  types  of  construction  in  which  due  advan- 
tage can  be  taken  for  each  type,  of  all  the  possible  conditions 
favorable  to  its  particular  method  of  handling. 

Then,  with  his  first  costs  before  him,  he  must  weigh  against 


8  TRANSMISSION  LINE  CONSTRUCTION 

each  other  for  the  different  systems,  their  depreciation,  reliability, 
maintenance  cost  and  accessibility  for  repairs  and  maintenance. 
The  life  of  a  steel  tower  or  pole  is  estimated  at  from  twenty- 
five  to  forty  years.  With  proper  original  construction  and  careful 
maintenance,  however,  there  is  no  reason  why  it  should  not 
exceed  these  figures.  As  noted  in  Chapter  VI,  the  size  of  the 
tower  members,  the  quality  of  their  protection,  the  climate  and 
the  care  with  which  the  assembling  and  erection  of  the  structures 
were  effected  are  the  prime  factors  that  go  to  determine  the  life  of 
a  steel  structure. 

The  durability  of  a  reinforced  concrete  pole  is  not  as  yet 
established  satisfactorily;  claims  are  made  for  almost  eternal 
life,  but  it  will  be  interesting  to  note  the  long-continued  effects 
of  frost  and  the  elements  upon  them.  Another  feature  that 
appears  to  influence  the  durability  of  such  poles  is  the  effect  of 
the  whipping  and  vibratory  action  which  is  produced  by  the 
action  of  the  wind  on  the  line  conductors;  the  results  of  an  in- 
vestigation of  this  latter  effect  in  the  case  of  reinforced  poles  is 
given  in  the  chapter  on  Reinforced  Concrete  Poles.  As  far  as  can 
be  learned,  concrete  poles  that  have  been  in  service  for  five  to 
six  years  appear  to  be  in  first  class  condition  and  show  no  visible 
depreciation. 

The  life  of  wooden  poles  varies  with  the  kind  of  timber,  with 
climatic  conditions  and  with  the  particular  locations  in  which 
they  are  set.  Most  engineers  assume  a  life  of  about  ten  to  twelve 
years  for  white  cedar,  which  is  the  most  common  pole  timber. 
Treated  poles  of  various  kinds  will  average  twenty  years.  In 
preparing  estimates  for  a  particular  locality,  the  life  of  the  kind 
of  timber  it  is  proposed  to  use  should  be  ascertained  by  an  exami- 
nation of  existing  telephone,  telegraph  and  transmission  lines, 
supplemented,  wherever  possible,  with  careful  investigation  of 
the  construction  records  of  the  different  companies. 

As  far  as  can  be  ascertained  from  the  meager  data  available, 
concrete  is  the  cheapest  form  of  construction  to  maintain,  and 
steel  structures  come  next;  but,  as  will  be  discussed  later,  the 
quality  of  the  steel  and  the  character  of  the  protection  which  is 
given  to  it  make  the  cost  of  maintenance  a  variable  factor  for 
this  type  of  construction.  Wooden  construction,  of  course, 
requires  considerable  attention  after  the  first  few  years  of  service, 
varying  with  the  care  with  which  the  original  construction  work 
was  carried  out,  the  climatic  conditions  and  the  loads  to  which 


PRELIMINARY  WORK  9 

the  poles  are  subjected.-  Cross-arm  maintenance  must  be  con- 
sidered with  wooden  construction  and  also  with  steel  and  con- 
crete structures  employing  wooden  arms.  This  factor  may  be 
great  or  small  depending  upon  the  safety  factor  of  the  insulator 
and  the  climatic  conditions.  For  instance,  the  salt  fogs  fre- 
quently encountered  in  certain  parts  of  the  West  often  increase 
the  leakage  current  sufficiently  to  destroy  the  arms. 

The  insulation  maintenance  for  a  type  of  construction  which 
employs  the  longer  spans  is  naturally  lowered  with  the  decrease 
in  the  total  number  of  points  of  support.  Nevertheless,  the 
question  may  arise  as  to  whether  or  not  insulators  which  work 
under  a  heavier  mechanical  strain  where  long  spans  are  used  are 
any  more  susceptible  to  electrical  failure  than  those  where  short 
spans  are  supported,  even  though  the  load  in  both  cases  is  well 
within  the  limits  of  the  insulator.  However,  nothing  that 
would  indicate  such  a  condition  has  ever  come  to  the  attention 
of  the  writer,  although  it  is  very  apparent  in  strain  insulators. 
Where  the  same  insulator  is  used  to  carry,  say  a  250,000  or 
300,000  circ.  mil  copper  cable  in  250-ft.  and  5CO-ft.  spans 
respectively,  the  relative  failure  would  in  all  probability  be 
greater  on  the  long  span  line. 

As  to  reliability  we  must  place  steel  first,  and  concrete,  based 
upon  its  performance  up  to  the  present  time,  next.  Steel  is  not 
injured  by  the  direct  stroke  of  lightning  and  is  immune  from 
damage  by  grass  fires,  birds,  insects,  etc.  These  conditions  may 
also  be  said  to  apply  to  concrete,  although  there  is  a  question  in 
the  writer's  mind  as  to  the  effect  of  a  direct  stroke  of  lightning 
upon  a  wet  concrete  pole.  It  would  appear  that  there  is  great 
liability  that  the  concrete  outside  of  the  steel  reinforcement  will 
spall  off  under  these  circumstances,  but  in  the  concrete  trans- 
mission line  work  of  the  Marseilles  (111.)  Land  &  Water  Company, 
this  has  occurred  in  but  one  instance  and  then  to  a  slight  extent 
at  the  top  and  the  ground  line  only.  Wooden  pole  construction 
is  easily  damaged  by  lightning,  although  this  trouble  is  decreased 
to  a  great  extent  by  the  installation  of  ground  w^ires,  which  could 
also  probably  be  used  to  advantage  in  concrete  pole  work.  An- 
noying damage  and  interruption  to  the  service  with  wooden  con- 
struction are  caused  very  frequently  by  grass  fires,  especially 
where  the  line  is  built  along  a  road  or  parallel  to  a  railroad 
right-of-way. 

As  far  as  accessibility  is  concerned,  the  question  lies  in  the 


10  TRANSMISSION  LINE  CONSTRUCTION 

form  of  the  structure  and  not  the  material.  Poles- can  often  be 
used  to  gain  this  advantage  where  the  room  required  by  a  tower 
would  prohibit  its  use.  Sometimes,  however,  as  in  the  case  of 
utilizing  the  public  highways,  either  longer  poles  or  shorter  spans 
than  would  be  necessary  on  a  private  right-of-way  may  have  to 
be  used  in  order  to  maintain  safe  overhead  clearances.  Hence 
the  limits  in  this  regard  must  be  taken  into  consideration. 

In  conclusion,  it  may  be  said  that,  leaving  concrete  out  of  the 
discussion  for  a  complete  line  at  the  present  time,  owing  to  its 
untried  possibilities  and  to  the  fact  that  it  generally  requires 
that  the  company  manufacture  its  own  poles,  steel  construction 
of  some  kind,  as  a  straight  business  proposition,  will  usually  be 
found  preferable  for  high-tension  transmission  work,  excepting  in 
a  few  isolated  cases  where  the  existing  financial  considerations 
demand  the  lowest  possible  first  cost,  regardless  of  quality, 
depreciation  and  maintenance,  or  where  the  location  is  such 
that  pole  timber  is  available  at  such  a  low  figure  as  to  offset  these 
items.  Even  then  the  question  of  reliability  must  be  carefully 
considered. 

Concrete  may  prove  itself  a  factor  in  the  situation  in  the  near 
future  for  with  the  interest  now  being  shown,  its  possibilities 
will  no  doubt  be  developed  in  the  next  few  years. 


CHAPTER  II 
LOCATION  OF  LINE — SURVEYS  AND  ENGINEERING 

With  the  route  of  the  line  and  the  type  of  construction  settled 
to  his  satisfaction,  the  engineer  is  ready  to  make  his  location  or 
staking-out  survey.  This  may  be  either  a  stadia  or  chain  survey, 
depending  upon  the  type  of  construction  to  be  employed  and  the 
character  of  the  country.  If  the  line  be  through  rough,  hilly 
country,  the  stadia  will  usually  be  preferable,  but  in  well-settled 
districts,  chaining  wrill  generally  be  found  the  more  rapid  and 
economical,  especially  in  short  span  construction.  A  party  of 
from  two  to  four  will  be  large  enough  to  do  the  work  efficiently, 
where  it  is  possible  to  pick  up  an  extra  man  as  axeman  when 
heavy  brush  or  timber  is  encountered,  though  of  course  this 
practice  will  be  impossible  in  remote  regions,  where,  if  the  going 
is  likely  to  be  heavy  at  times,  it  will  be  well  to  carry  an  extra 
man,  but  as  in  this  case  it  will  very  likely  be  necessary  to  carry 
a  light  camping  outfit,  the  extra  man  can  also  help  to  take  care 
of  the  camp  when  he  is  not  required  in  the  field.  Generally  a 
line  surveying  party  will  be  able  to  secure  accommodations  along 
its  route  in  most  sections  of  the  country,  and  will  not  be  obliged 
to  maintain  much  of  a  camp.  It  is  not,  however,  within  the 
scope  of  this  book  to  discuss  details  of  a  survey  other  than  those 
affecting  its  purpose  as  a  step  in  transmission  line  work,  and  the 
reader  is  referred,  therefore,  to  some  one  of  the  many  good  works 
on  surveying  practice  for  more  extended  information  as  to  the 
handling  and  maintenance  of  a  field  party. 

The  surveying  crew  should  be  equipped  with  a  light  transit, 
which,  if  stadia  work  is  to  be  done,  should  have  either  a  vertical 
arc  or  a  full  vertical  circle  and  stadia  cross-hairs.  Depending 
upon  the  kind  of  survey,  the  men  will  be  provided  also  with 
chains,  tapes,  two  or  three  8-ft.  flag-poles,  level  rod,  stadia  board, 
preferably  about  14  ft.  long,  axes,  etc. 

In  making  the  staking-out  survey,  there  are  three  general  ways 
of  carrying  out  the  work:  First,  where  a  preliminary  survey  of 
the  route  has  been  made  and  a  profile  prepared,  the  towers  or 

11 


12  TRANSMISSION  LINE  CONSTRUCTION 

poles  are  located  on  this  in  the  office  and  the  field  party  stakes 
them  out  on  the  ground  with  the  profile  as  a  guide;  second,  where 
no  preliminary  survey  has  been  made,  in  which  case  the  crew 
runs  out  the  line  in  100-ft.  stations  and  carries  the  levels  the  same 
as  for  a  railroad  survey,  though  not  as  a  rule  carrying  the  work  on 
to  the  same  degree  of  accuracy,  sometimes  reading  only  the  eleva- 
tions to  the  nearest  1/2  ft.,  though  they  should  be  taken  to  the 
nearest  tenth  to  make  possible  better  checks  with  bench  marks; 
third,  where  no  preliminary  survey  has  been  made  and  the  party 
locates  the  structures  as  it  goes,  recording  lengths  of  spans,  etc., 
and  taking  elevations  at  the  points  of  locations  and  also  at  enough 
intermediate  points  to  give  data  for  a  relatively  accurate  profile 
in  cases  of  higher  or  lower  intervening  ground  or  of  abrupt  changes 
in  slope.  By  relatively  accurate  is  meant  the  securing  of  close 
readings  at  the  locations  of  structures  to  allow  of  their  heights 
for  proper  grading  being  determined,  and  then  enough  inter- 
mediate elevations  taken  so  that  the  clearance  of  the  low  point 
of  the  spans  to  ground  can  be  closely  ascertained. 

The  first  method  is  probably  the  one  most  generally  used  for 
heavy  tower  line  construction.  The  work  of  the  party  in  the  field 
consists  merely  of  taking  its  data  from  the  profile,  measuring  off 
the  spans  as  called  for  and  driving  stakes  in  accordance  with  the 
numbers  indicated  on  the  profile;  this  method  is  open  to  the 
objection  that  what  appears  to  be  the  most  favorable  point  of 
location  on  paper  may  be  the  poorest  one  for  the  economical  con- 
struction in  the  field.  Unless  one  of  the  party  is  conversant  with 
good  line  construction  and  can  be  relied  upon  to  make  advan- 
tageous changes  from  the  lay-out  on  the  profile  where  it  appears 
desirable,  it  is  likely  to  result  in  a  high  first  cost  with  poorer 
construction,  possibly,  in  addition.  Following  this  method  of 
staking  out,  especially  for  tower  lines,  the  work  can  be  carried 
on  very  rapidly  and  economically  with  a  stadia  instrument. 
Where  the  locations  are  made  on  paper  in  the  office,  it  is  a  wise 
plan  to  check  clearances  to  ground  in  the  field  in  places  where 
there  is  a  rise  of  ground  or  abrupt  change  of  slope  between 
towers,  where  the  line  passes  up  or  down  steep  side  hills;  also  if  it 
is  built  on  or  along  steep  slopes  where  the  line  of  the  survey  may 
show  ample  clearance  for  conductors  at  the  center  line  indicated 
on  the  profile,  whereas  actually  the  uphill  conductors  may  be 
dangerously  close  to  ground. 

In  carrying  out  the  work  as  outlined  in  the  second  method, 


LOCATION  OF  LINE  13 

which  is  best  adapted  to  wooden  pole  work  and  cases  where  no 
preliminary  survey  has  been  made,  the  crew  makes  no  attempt 
to  locate  any  of  the  structures,  merely  running  out  the  line  in 
100-ft.  stations,  taking  the  levels  and  noting  the  general  topog- 
raphy and  the  ground  conditions,  leaving  to  the  construction 
foreman  the  responsibility  for  the  actual  pole  or  tower  location 
and  the  proper  lining-in,  the  profile  furnishing  the  foreman  with 
the  necessary  data  as  to  pole  heights  and  spans.  In  staking  out, 
the  foreman  will  have  the  station  stakes  to  refer  to  for  line  and 
general  distances. 

Following  the  third  method,  the  surveying  party  is  given  the 
paper  location  of  the  line,  as  decided  upon  after  investigation  on 
the  ground.  It  stakes  out  the  center  locations  of  the  structures 
at  points  most  suitable  under  the  conditions  as  determined  in  the 
field,  adhering  of  course  to  a  standard  spacing  as  closely  as  is 
practicable,  and  at  the  same  time  taking  levels  at  stations  and 
such  intermediate  points  as  may  be  necessary  to  give  all  data 
needed  in  determining  heights  of  structures  both  for  clearance  and 
for  horizontal  grading  of  the  line.  With  this  method,  as  well 
as  with  the  first,  it  is  essential  that  one  of  the  party  be  a  man 
experienced  in  practical  line  construction,  capable  of  deciding 
any  question  that  may  arise  as  to  spans,  angles,  foundations,  etc. 

In  staking  out  tower  locations,  it  has  been  usual  in  light  mod- 
erate-span construction  to  set  only  a  center  stake  as  in  wooden 
pole  work.  This  practice  has  also  been  followed  in  some  heavy 
work.  It  is  evident,  however,  that  with  the  long  spans  employed 
in  tower  work,  this  method  of  staking  cannot  result  in  very  good 
alignment.  To  make  a  good  workmanlike  job  possible,  a  refer- 
ence or  lining  stake  should  be  set.  This  stake  should  be  located 
a  short  distance  outside  of  the  anchors  and,  with  the  center  hub, 
it  will  give  the  setting  foreman  a  reference  line  by  means  of 
which  he  can  bring  his  templet  into  the  proper  position.  In 
some  instances  two  lining  stakes,  one  on  each  side  of  the  center 
stake,  have  been  used,  but  one  stake  will  give  the  same  results. 

In  connection  with  the  staking  out,  it  is  proper  to  consider 
here  some  of  the  features  that  determine  the  location  of  line 
supports  in  first-class  construction  practice,  with  special  reference 
to  those  that  frequently  will  have  to  be  settled  in  the  field. 

The  first  question  is  that  of  the  maximum  allowable  angle  or 
" corner"  that  the  surveying  crew  may  assume  to  carry  on  one 
structure;  in  the  past,  in  wooden  pole  construction,  it  has  been 


14  TRANSMISSION  LINE  CONSTRUCTION 

the  custom  to  carry  on  one  pole  a  maximum  corner  of  15  degrees, 
splitting  the  angle  up  between  two  or  more,  where  it  exceeded  this 
limit.  However,  with  the  advent  of  steel  structures  and  better 
insulators  and  pins,  one  now  often  sees  angles  up  to  60  degrees, 
and  sometimes  right  angles,  carried  on  one  specially  designed 
structure  which  is  provided  with  a  number  of  insulators  propor- 
tionate to  the  strain  developed  by  the  angle  and  spans  on  either 
side;  with  the  strain  type  of  suspension  insulators  at  angles,  the 
handling  of  corners  is  greatly  simplified,  and  with  special  designs 
of  structures  almost  any  problem  in  this  line  can  be  solved. 
Under  ordinary  circumstances,  however,  it  is  well  to  limit  the 
angle  on  any  one  structure  to  a  maximum  of  about  45  degrees 
and  to  use  one  standard  angle  tower  for  the  whole  construction. 
This  will  avoid  the  relatively  great  expense,  both  in  material  and 
labor,  of  special  structures  of  varying  design.  Excepting  possibly 
where  right-of-way  difficulties  are  encountered,  a  maximum 
angle  of  45  degrees  need  not  be  exceeded.  Where  an  angle 
greater  than  45  degrees  appears  necessary,  it  should  be  made  the 
subject  of  careful  study  before  approval.  In  some  instances  in 
high-tension  work,  buck-arms  have  been  used  in  wooden  pole 
construction,  but  this  is  not  standard  construction  for  high  vol- 
tages and  it  should  not  be  employed  where  any  other  solution  is 
possible;  for  any  heavy  corner  two  structures  are  better  than  one 
because  with  failure  of  either  one  of  them  the  other  will  at  least 
prevent  the  whole  construction  from  coming  down. 

It  is  in  building  a  line  along  or  closely  parallel  to  a  highway, 
that  the  ingenuity  of  the  engineer  is  taxed  to  the  utmost  in  over- 
coming " corner"  difficulties  as  introduced  by  the  turns  and 
twists  of  the  road  and  at  the  same  time  the  lack  of  guy  room. 

Where  deflections  of  more  than  10  degrees  occur,  the  strain 
should  be  minimized  by  shortening  up  the  spans  on  either  side  of 
the  corner,  making  them  about  three-fourths  the  standard  length 
for  angles  of  from  10  degrees  to  20  degrees  and  down  to  two- 
thirds  or  three-fifths  of  the  normal  for  angles  greater  than  that; 
at  dead-ends  also  the  last  span  should  be  only  about  three-fifths 
of  the  standard. 

Another  point  on  which  the  men  should  be  instructed  is  the 
location,  within  reasonable  limits,  of  the  structures  so  as  to  assist 
in  the  grading  of  the  line  as  much  as  possible;  often  the  moving 
of  a  pole  or  tower  relatively  a  few  feet  one  way  or  another,  will 
make  it  possible  to  use  a  standard  structure  where  otherwise  one 


LOCATION  OF  LINE  15 

of  an  odd  size  would  have  been  called  for  to  maintain  the 
horizontal  grade.  Where  bad  ground  is  encountered  attention 
should  be  given  to  seeking  the  best  foundation  under  the  cir- 
cumstances. In  cases  of  long  spans  it  is  better  to  increase  a 
span  a  trifle  than  to  locate  the  towers  on  costly  foundations. 

The  crew  should  also  use  particular  care  in  marking  plainly  and 
setting  solidly  the  location  and  reference  stakes  for  the  structures 
so  that  in  carrying  out  the  construction  work  later  on,  the  mate- 
rial distribution  and  erection  crews  will  be  able  to  do  their  work 
accurately.  The  surveying  party  should  also  be  cautioned 
against  any  unnecessary  axing  or  other  damage  to  property.  It 
should  seek  to  carry  on  its  work  in  a  gentlemanly  manner, 
without  arousing  any  enmity  through  careless  or  unnecessary 
trespass. 

All  surveys  should  be  tied  in  with  section  corners  and  salient 
topographical  features  so  that  they  can,  if  necessary,  be  put  on 
record,  as  well  as  platted  accurately,  regardless  of  whether  or  not 
the  line  is  to  be  built  on  private  right-of-way,  under  leased 
rights  or  on  public  highways.  While  the  location  work  is  being 
carried  on  in  the  field,  an  accurate  map  of  the  complete  system, 
in  sections  as  desired,  should  be  made.  For  this  map  the  writer 
has  found  a  scale  of  2  in.  to  the  mile  to  be  very  satisfactory, 
since  this  scale  is  generally  employed  in  county  plat  books  and 
permits  the  transferring  of  details  without  change  of  scale.  The 
holdings  of  the  various  property  owners  along  the  entire  length 
of  the  line  should  be  indicated  and  marked  on  this  map.  In 
this  way,  the  map  will  be  useful  not  only  for  the  right-of-way 
men,  but  also  for  giving  the  construction  foremen  reference 
points  in  directing  the  work.  The  map  will  also  show  all  other 
features  included  on  a  map  of  that  size,  locating  accurately  the 
various  farm-houses  and  buildings,  streams,  roads,  bridges, 
railroads,  fords,  etc.  It  should  indicate  all  crossings  of  the 
transmission  line  with  existing  power,  telegraph  or  telephone 
lines.  The  transmission  line  route  as  finally  located  should  be 
laid  out  with  all  details  as  to  deflections,  etc.,  together  with 
numerous  reference  points  on  tangent;  further,  the  insertion  of 
the  station  numbers  on  either  side  of  such  division  line  as  streams, 
railroads  and  high  ridges  will  assist  the  distribution  foreman  in 
directing  that  part  of  the  work. 

A  profile  of  the  line  is  made  upon  the  completion  of  the  survey, 
unless  it  has  already  been  prepared  as  will  be  the  case  if  the  first 


16  TRANSMISSION  LINE  CONSTRUCTION 

method  of  laying  out  a  line  has  been  followed.  Usually  this 
profile  is  made  to  the  same  scale  as  railroad  profiles  on  standard 
cross-section  paper,  platting  400  ft.  to  the  inch  horizontal  and 
20  ft.  to  the  inch  vertical.  The  transit  line  should  be  shown  on 
the  bottom  of  the  sheet  as  is  customary  in  railroad  work.  Angles 
and  all  road,  stream,  railway  and  line  crossings  should  be  laid  out 
with  any  necessary  data  referring  to  same,  and  the  profile  should 
show  height  out  of  ground  of  all  poles  carrying  lines  to  be  crossed 
with  data  as  to  the  number  of  cross-arms  and  wires  on  the  same. 

The  next  act  is  the  location  on  this  profile  of  the  structures  or 
at  least  the  determination  of  their  heights,  etc.,  where  the  second 
or  third  survey  methods  have  been  followed.  If  the  first  method 
has  been  employed,  this  will  have  been  done  before  the  staking- 
out  party  took  the  field.  With  the  second  method,  the  profile 
as  laid  out  in  100-ft.  stations  is  taken  and,  with  the  standard 
height  of  structure,  the  standard  span  and  the  minimum  clearance 
to  ground  as  a  basis,  the  locations  of  the  poles  or  towers  and  their 
heights  (as  made  necessary  to  give  a  good  even  grade  free  from 
unusual  vertical  strains  on  the  insulators)  are  drawn  in.  Where 
poles  are  to  be  used,  only  the  height  out  of  the  ground  should  be 
shown,  as  indicated  on  the  typical  profile,  Fig.  1.  Towers,  how- 
ever, are  always  bought  on  the  basis  of  the  clearance  of  the  lowest 
conductor  to  ground,  and  are  generally  so  rated  when  the  height 
is  mentioned. 

Where  the  third  msthod  of  laying  out  a  line  is  followed,  the 
centers  of  the  structures  will  have  already  been  located  in  the 
field.  The  office  work  then  consists  in  determining  their  heights 
and  type  for  the  conditions  of  load  encountered. 

For  finding  the  clearance  to  ground  of  the  low  conductor,  where 
the  points  of  support  are  at  approximately  the  same  elevation, 
the  air  line  between  the  pin  tops  can  be  drawn  in  and,  deducting 
the  maximum  sag,  the  clearance  of  the  low  point  of  the  sag 
curve  to  ground  can  be  determined.  A  preferable  way  is  to  use 
a  templet  of  the  sag  curve  -laid  out  to  scale  on  a  piece  of  tracing 
cloth  or  celluloid,  for  in  this  way  a  check  can  be  secured  on  the 
clearance  to  all  intermediate  points  in  the  span.  As  the  clear- 
ance to  ground  need  not  usually  be  checked  where  the  line  is 
built  through  level  or  gently  rolling  country,  where  a  straight- 
line  method  would  give  the  information  satisfactorily,  it  is 
apparent  that  if  a  check  is  required  by  the  contour  of  the  ground, 
it  should  cover  all  the  points  intermediate  between  the  two  towers. 


LOCATION  OF  LINE 


17 


A  curve  templet  is  the  only  thing  that  will  give  these  last  data 
accurately.  Where,  as  in  rough  country,  the  points  of  support 
of  the  conductors  are  at  an  appreciable  difference  in  elevation, 


Of 


\ 


AS 


01 


of 


Of 


0? 


^ 


Of 


0) 


<T-f  96  T 


Sf 


os 


Of 


88 


68 


Cr- 


Of 


Of 


88 


68 


Of 


88 


18 


\ 


If 


Of 


68 


Of 


so  that  the  low  point  of  the  sag  will  not  come  at  the  middle  of  the 
span,  the  clearances  should  certainly  be  checked  closely. 

For  the  foregoing  work  and  for  the  location  of  structures  on 
2 


18  TRANSMISSION  LINE  CONSTRUCTION 

a  profile  to  give  a  required  clearance,  the  method  of  making  a 
universal  templet  on  celluloid  to  cover  the  probable  range  of 
span  lengths,  as  used  by  T.  Holmgren  in  the  transmission  line 
work  of  the  Trolhattan  project,  is  very  good.  This  method  can 
be  employed  to  solve  any  problem  involving  location  and  clear- 
ance of  structures  on  a  profile.  It  was  described  by  Mr.  Holm- 
gren in  the  Teknisk  Tidskrift,  Elektroteknik,  No.  3,  1910,  and  by 
J.  S.  Viehe  in  the  Electrical  World  for  June  15,  1911. 

In  laying  out  the  line  on  the  profile,  there  is  another  point  t'hat 
must  be  taken  into  consideration — namely,  the  condition  that 
may  arise  where  a  line  is  built  along  or  parallel  with  a  steep 
slope.  Here  the  profile  may  indicate  that  the  low  conductor  has 
ample  clearance  to  ground.  The  profile,  however,  shows  the 
same  for  the  center  line  of  the  towers.  It  is  apparent  from  this 
that  where  a  conductor  is  out  10  ft.  or  12  ft.  to  the  side  of  this 
center  line  the  clearance  of  the  conductors  on  the  uphill  side  of 
the  structures  may  easily  be  reduced  to  a  dangerous  point.  In 
such  cases  a  little  general  information  as  to  the  topography  of 
the  ground  on  either  side  of  the  line  of  survey,  as  noted  in  the 
discussion  of  surveying  methods,  will  be  of  value. 

With  the  completion  of  the  laying  out  of  the  line  on  the  pro- 
file and  map,  begins  the  work  of  making  up  the  bill  of  material 
required.  For  this  the  profile  sheets  are  the  "plans"  of  the 
construction.  From  them  are  determined  the  number  of  the 
various  standard  line  structures  needed,  and  the  angle,  trans- 
position, dead-end  and  other  special  types  required;  from 
these  data,  also  the  list  of  insulators,  pins,  cross-arms,  hardware, 
etc.,  as  may  be  called  for  by  the  type  of  construction,  together 
with  ties,  insulator  clamps,  etc.,  is  made  up.  From  the  data 
on  the  profile,  the  amount  of  wire,  with  an  allowance  of  from 
2  per  cent,  to  5  per  cent,  for  sag  and  waste,  is  also  determined. 

In  making  up  estimates  of  material  it  must  be  borne  in  mind 
that  contingencies  such  as  slight  changes  in  spacing  or  detours 
due  to  right-of-way  demands,  accidents  in  the  course  of  con- 
struction, etc.,  must  be  allowed  for  and  amounts  ordered  accord- 
ingly. A  contingency  allowance  of  1  per  cent,  to  3  per  cent., 
depending  upon  the  magnitude  of  the  work,  will  be  a  good 
insurance  against  delay  in  the  construction;  much  of  this  mate- 
rial will  be  required  for  stock  in  taking  care  of  the  repairs  and 
maintenance  upon  beginning  operation,  so  that  the  amounts 
need  not  be  cut  to  a  minimum.  All  estimates  should  be  made 


LOCATION  OF  LINE  19 

up  by  two  persons  independently  and  checked  against  each 
other  to  avoid  possibility  of  errors. 

Next  follows  the  matter  of  shipment,  that  is,  to  say,  the 
amounts  of  material  which  are  to  be  delivered  at  the  various 
shipping  points  serving  the  territory  traversed  should  be  listed. 
If  necessary,  portions  of  the  total  of  an  item  may  be  shifted 
from  one  point  to  another,  so  as  to  bring  all  of  the  shipments 
into  car-load  lots.  From  his  knowledge  of  the  various  roads 
radiating  from  the  different  towns,  the  engineer  will  be  able 
so  to  arrange  his  shipping  schedule  as  to  take  advantage  of  the 
possibilities  of  a  cheaper  long  haul  on  a  good  road  over  that 
of  a  costlier  shorter  one  on  a  bad  road.  Consideration  should 
also  be  given  to  the  teaming  facilities  at  the  different  stations. 
In  small  communities,  especially  in  winter,  it  is  often  possible 
to  secure  a  man  and  team  to  haul  poles  or  towers  for  as  low  as 
$3.50  a  day,  where  in  larger  towns  the  same  service  will  cost 
from  $4  to  $5.  It  is  also  good  policy  to  make  general  inquiries 
regarding  the  number  of  teams  that  will  be  available  for  use 
in  the  distribution  of  material  at  the  season  6f  the  year  that 
they  will  be  needed.  Another  feature  that  is  very  relevant 
to  the  matter  of  shipping  instructions  is  the  question  of  unload- 
ing and  storage  facilities  for  delivered  material.  Poles  or 
towers  require  ample  space  along  a  side  track  where  they  can 
be  unloaded  and  arranged  systematically  for  ease  and  economy 
in  hauling  out  for  distribution;  insulators  should  be  under 
cover  where  they  will  be  safe  from  breakage,  or  at  least  they 
should  be  stored  where  they  will  not  be  too  subject  to  the  care- 
less investigation  of  the  curious  public.  Copper  wire,  so  subject 
to  mysterious  disappearance,  should  be  kept  under  lock  and 
key. 

With  all  these  considerations  in  mind,  a  shipping  schedule 
can  be  made  up  for  the  suitable  points  of  shipment  and  pro- 
posals can  be  asked  for,  f.o.b.  these  points,  thus  putting  all 
bidders  on  the  same  basis.  If  the  weights  assumed  in  making 
up  the  material  estimates  and  shipping  information,  differ  from 
those  proposed,  they  will  require  checking  to  see  that  the  car- 
loading  will  be  satisfactory.  It  often  happens  that  proposals 
are  invited  before  the  estimates  are  complete.  Then  the  request 
is  for  bids  on  the  various  materials  based  upon  approximate 
amounts,  the  bids  to  give  the  unit  price  of  each  delivered  in 
car-load  lots  at  the  several  specified  stations.  With  the  com- 


20  TRANSMISSION  LINE  CONSTRUCTION 

pleted  estimates  and  the  data  of  the  bids,  detail  shipping  instruc- 
tions are  then  made  out. 

The  right-of-way  problem  is  always  the  most  annoying  step 
in  line  construction.  The  first  matter  to  be  settled  is  whether 
the  right-of-way  is  to  be  bought  outright  or  acquired  under 
easement.  It  is  not  very  often,  except  in  cases  of  important 
undertakings  maintaining  a  private  road  along  their  lines,  that 
title  is  acquired  to  a  transmission  line  right-of-way,  because 
under  ordinary  circumstances  it  is  a  good  deal  cheaper  and 
as  satisfactory  to  secure  the  right  to  locate  and  maintain  struc- 
tures on  a  piece  of  property  under  easement.  This  applies  to 
the  first  cost  as  well  as  to  the  operation  of  the  line.  Where  a 
strip  of  land  is  bought  outright  the  cost  is  always  relatively 
high,  the  land  is  subject  to  taxes  and  other  assessments,  and 
fences  are  generally  required  along  each  side  of  the  right-of-way 
line.  In  many  cases  it  may  be  that  the  outright  purchase  of 
the  right-of-way  may  prove  economical,  especially  in  sparsely 
settled  districts,  but  the  method  that  is  now  generally  followed 
in  good  transmission  line  practice,  is  to  pay  so  much  per  struc- 
ture for  the  perpetual  right  and  easement — sometimes  this  is 
for  a  limited  term  of  years,  with  provisions  for  renewal  at  expi- 
ration— to  erect  and  maintain  a  line  of  poles  or  towers  and 
wires  upon  the  described  property  in  accordance  with  the  sur- 
vey, allowing  for  necessary  guys  and  braces,  with  full  right  to 
remove  for  a  given  distance  on  either  side  all  trees  which  are 
dangerous  to  the  operation  of  the  line. 

To  meet  the  demands  of  the  contracting  parties,  special 
clauses,  such  as  a  provision  to  reimburse  the  property  owner  for 
possible  damage  to  his  growing  crops  in  the  construction  of  the 
line,  will  often  have  to  be  incorporated.  In  all  cases,  no  matter 
how  worthless  a  piece  of  property  or  how  obscure  the  highway 
traversed,  right-of-way  contracts  should  be  secured  for  every 
pole  or  anchor  set,  for  not  only  does  the  actual  right-of-way  cost 
itself  increase  wonderfully  after  construction  sets  in,  but  the 
delay  in  the  work  and  the  cost  of  coming  back  to  clean  up  skipped 
work  will  be  found  very  annoying  and  expensive.  Some  com- 
panies do  not  pay  as  much  attention  as  they  should,  to  the 
securing  of  rights  to  set  along  highways,  as  they  assume  that 
their  state  charter  or  township  authorization,  is  all  that  is 
necessary.  Ordinarily  this  authorization  is  sufficient  for  the 
setting  of  the  poles  but  it  cannot  include  any  rights  to  trim 


LOCATION  OF  LINE  21 

trees  and  set  anchors  inside  of  fences,  etc.,  which  are  the  main 
features  in  a  highway  right-of-way  contract. 

A  form  of  contract  for  the  acquirement  of  right-of-way  under 
easement  is  given  below.  This  form  has  been  found  satisfactory 
by  several  companies  in  the  Middle  West.  Contracts  should  be 
recorded  in  the  same  manner  as  any  other  agreement. 


FORM  1. 


part         of  the  first  part  in  consideration  of Dollars 

($ )  to paid  by  WESTERN  WATER  POWER  Co., 

a  Wisconsin  corporation,  authorized  to  do  business  in  Wisconsin,  receipt  of 
which  is  hereby  acknowledged,  do  hereby  convey  and  warrant  unto 

said  WESTERN  WATER  POWER  Co.,  second  party,  its  successors  and  assigns, 
the  perpetual  right  and  easement  to  erect  and  maintain  a  line  of  poles  and 
wires  with  all  necessary  anchors,  guys  and  braces  over  and  across  land 

owned  by  first  part in  Township  of 

County  of State  of  Wisconsin,  described  as 

follows,   to- wit: 


The  route  to  be  taken  by  said  pole  line  across  said  land  being  more 
specifically  described  as  follows: 


Together  with  the  right  to  enter  upon  said  premises  for  the  purpose  of 
erecting  such  poles  and  supports  and  stringing  said  wires  and  repairing  or 
removing  the  same,  and  the  right  to  trim  or  remove  such  trees  as  interfere 
with  said  line. 

WITNESS  the  hand  and  seal  of  part         of  the  first  part  this 

day  of  A.  D.,  190 

In  presence  of 

L.  S. 
....L.  S. 


22  TRANSMISSION  LINE  CONSTRUCTION 

STATE  OF  WISCONSIN, 


County   of.. 


SS. 


On  this day  of 


A.  D.  190  ,  before  me,  a  Notary  Public  in  and 

for  said  County,  personally  appeared 

...  to  me  known  to  be  the  same  person 

described  in  and  who  executed  the  within  instrument  who 

acknowledged  same  to  be free  act  and  deed. 


Notary  Public. 
My  commission  expires 

The  way  the  work  of  securing  the  right-of-way  is  carried  on 
and  the  personality  of  the  man  who  represents  the  company, 
has  much  to  do  with  determining  the  future  sentiment  shown 
toward  the  company.  It  is  poor  business  to  pay  more  for  a 
privilege  than  it  is  worth,  but  it  is  even  poorer  policy  to  get  the 
better  of  the  bargains  through  sharp  practices  and  so  leave 
behind  a  trail  of  dissatisfied  property  owners.  A  few  dollars 
extra  spent  in  purchasing  right-of-way  will  be  more  than  repaid 
in  the  good-will  obtained.  Anyone  who  bears  the  responsibility 
for  continuity  of  operation  of  a  high  tension  line  can  testify  to  the 
inestimable  value  of  the  friendship  of  the  people  along  the  line. 

The  cost  of  right-of-way  naturally  varies  with  the  character 
of  the  country;  on  highways  in  the  Middle  West  for  a  high 
tension  line  built  in  1908-09,  the  cost  per  pole  varied  from  50 
cents  to  $5  depending  upon. the  amount  of  tree  trimming  and 
clearing  necessary;  along  section  lines  the  cost  ran  from  50  cents 
to  $2  per  pole,  and  where  the  line  ran  diagonally  through  fields 
or  at  some  distance  in  from  fences,  from  $2  to  $10  per  pole. 
The  averages  under  the  three  different  conditions  were,  for  the 
first  about  75  cents,  for  the  second  $1,  and  for  the  third  about  $5. 
This  line  ran  through  a  well-settled  community  where,  however 
the  land  value  would  not  average  over  $50  to  $60  per  acre.  The 
prices  given  are  for  a  perpetual  right  and  easement  to  erect  and 
maintain  the  line,  and  they  include  all  cutting  and  trimming 
privileges  for  a  distance  of  25  ft.  on  each  side  of  the  line.  In 
special  cases  separate  purchase  was  made  of  such  tall  trees  outside 
of  the  25  ft.  limit  as  were  deemed  dangerous. 

The  right-of-way  under  easement  for  a  tower  line  built  through 
sparsely  settled  territory  in  the  Middle  West  was  about  $9  per 
tower,  and  where  it  passed  through  well-settled  country  about 


LOCATION  OF  LINE 


23 


$20.  Another  tower  line  in  the  same  locality,  but  passing 
through  well-settled  country,  averaged  $26.50  per  tower  for 
right-of-way. 

In  making  final  preparations  for  the  beginning  of  the  construc- 
tion work  much  assistance  can  be  given  the  line  foreman  by 
furnishing  him  with  his  general  data  worked  up  in  compact 
form.  One  handy  little  kink  that  the  writer  has  used  is  a  small 
typewritten  book  made  up  as  shown  in  Fig.  2.  This  book 
gives  the  length  of  pole  or  height  of  tower  required  at  each 
location  and  notes  all  special  construction,  corners,  lengths  of 
span;  further,  where  a  structure  location  is  at  or  near  some 


470-40  ft. 
71^0  ft. 

Xing  Le  Blond  farm  road. 
72-43  ft. 

73-42  ft. — Due  east  Le  Blond  house. 
74-40  ft. 
475-45  ft. 
76-50  ft. 

— From  here  on  haul  from  Nedford- 
77-35  ft. 

100  ft.  span. 
78-40  ft.— A  8  deg.  R— Dbl.  Arm. 

100  ft.  span. — 8  ft.  top  for  78 
79-40  ft. 


FIG.  2. — Data  book  for  construction  foremen. 

land-mark  or  close  by  a  farm-house,  it  is  indicated  so  as  to  give 
the  construction  men  numerous  points  of  reference  in  doing  the 
work.  The  foreman  should  also  have  copies  of  all  shipping 
instructions  and,  supplementary  to  them,  definite  distribution 
instructions  to  direct  him  concerning  the  various  roads  to  be 
used  in  hauling  out  the  material  for  the  different  sections,  for 
instance  "from  No  235  to  No.  307  use  the  main  road  running 
due  north  from  Aville,"  etc.  Duplicates  of  all  right-of-way 
contracts  should  also  be  furnished  to  the  general  foreman  together 
with  the  property  map  of  the  route  on,  which  is  shown  the  name 
of  every  property  owner  with  whom  dealings  have  been  had  in 
securing  location  privileges.  These  contracts  will  state  in 
detail  the  number  and  location  of  the  structures  to  be  set,  the 


24  TRANSMISSION  LINE  CONSTRUCTION 

guying  that  is  to  be  done  and  the  trimming  and  cutting  of  trees 
and  shrubbery  that  has  been  agreed  upon.  It  will  also  give 
explicit  authorization  to  the  foreman  of  the  rights  acquired 
under  that  particular  agreement. 

All  data  and  instructions  to  be  furnished  line  foremen  should 
be  as  simple  and  explicit  as  possible. 


CHAPTER  III 
TYPES  OF  CONSTRUCTION 

The  wooden  pole  is  to-day  most  widely  employed  for  the 
support  of  transmission  lines,  but  with  the  increase  in  the  cost 
of  good  pole  timber  and  the  advent  of  cheaper  and  more  scientific 
steel  construction,  not  to  mention  the  pioneer  work  with  rein- 
forced concrete,  it  is  only  a  question  of  a  few  years  when  it  will 
be  superseded  for  transmission  lines  of  any  importance  at  all. 
Furthermore,  power  consumers  are  exacting  continuity  of 
service,  so  that  the  line,  always  the  part  of  the  power  system 
most  susceptible  to  damage  and  hardest  to  repair,  must  utilize 


FIG.  3. — Commonwealth  Power  Co.'s  standard  pole  top  construction  40,000- 
and  60,000-volt  transmission. 

the  construction  that  will  give  it  the  greatest  reliability.  This 
insistance  upon  uninterrupted  service,  combined  with  the  high 
maintenance  and  increasing  first  cost  of  wooden  construction, 
will  hasten  the  departure  of  the  wooden  pole  line. 

Wooden  poles,  as  generally  used  in  lengths  of  from  25  to  75  ft., 

25 


26 


TRANSMISSION  LINE  CONSTRUCTION 


are  spaced  from  100  to  200  ft.  apart.  The  length  of  span  most 
used  varies  from  125  ft.  to  130  ft.,  which  gives  a  high  factor  of 
safety  with  the  comparatively  few  wires  ordinarily  installed. 
This  condition  obtains  only  during  the  first  few  years  of  service 
because  the  pole  rapidly  decreases  in  strength  from  the  day  it  is 
set.  A  pole  less  than  35  ft.  long  is  rarely  used  as  standard  owing 
to  the  clearance  required  by  high-tension  circuits.  Legal  re- 
quirements for  heights  above  roads,  etc.,  usually  call  for  clear- 
ances that  demand  a  pole  at  least  30  ft.  long.  The  size  of  the 


FIG.  4. — Typical  single  circuit  pole  top  where  no  ground  wire  is  carried. 

top  varies  with  the  loading.  The  average  good  construction  in 
this  country  may  be  said  to  employ  35-ft.  or  40-ft.  poles  with 
7-in.  or  8-in.  tops  as  the  standard. 

A  good  example  of  Eastern  and  Middle  Western  pin-type 
construction  with  ground  wire  is  shown  in  Fig.  3.  This  is  the 
pole  top  used  by  the  Commonwealth  Power  Company  and 
several  other  companies  for  50,000-volt  and  60,000-volt  lines. 


TYPES  OF  CONSTRUCTION 


27 


As  originally  used  in  Michigan,  the  line  was  built  with  7-in.  top, 
3o-ft.  northern  cedars  as  standard  set  in  125  ft.  spans.  Similar 
construction  in  Wisconsin  employed  40  ft.  cypress  in  125-ft. 
spans,  three  No.  2  equivalent  copper  strand  conductors,  a 


.fS. — Pole  top,  using  pipe  pins. 


FIG.  6. — Ridge  pin. 

ground  wire,  cross-arms  of  5  in.  X  7-in.  yellow  pine,  a5-ft.  top  arm 
and  an  8-ft.  bottom  arm,  5  ft.  below. 
Figure  4  shows  a  typical  arrangement  where  no  ground  wire  is 


28 


TRANSMISSION  LINE  CONSTRUCTION 


carried.  The  only  point  in  which  the  construction  with  different 
companies  varies  much  is  in  the  manner  of  attaching  the  top  pin. 
Some  early  lines  have  used  a  wooden  pin  which  was  set  into  a 
hole  bored  into  the  top  of  the  pole  and  fastened  with  a  3/8-in. 
through-bolt.  Others  have  designed  an  angle  arrangement  for 
holding  the  top  pin  as  shown  in  Fig.  5  to  enable  the  same  type  of 
pipe  pin  to  be  used  at  the  top  as  on  the  arms,  which  is  a  valuable 
feature  where  the  whole  pin  is  in  one  piece  and  cemented  into  the 
insulators.  In  late  years  a  ridge  pin  such  as  the  one  shown  in 


O 


FIG.  7  (a,  b,  c.) — Pole  top  pins. 

Fig.  6  has  been  used  much  for  the  lower  voltages,  while  a  type 
similar  to  that  illustrated  in  Fig.  7  (a,  b,  c)  has  been  employed 
for  high  voltages.  In  other  details,  the  pole  tops  for  a  single 
circuit  without  ground  wire  have  been  carried  out  in  practically 
the  same  way. 

In  the  Southern  Power  Company's  construction,  the  ground 
wire  is  carried  on  a  pipe  extension  through-bolted  at  its  lower  end 
to  the  pole  and  braced  against  and  by  a  special  pole  top  casting 
which  also  supports  the  top  insulator.  This  type  is  shown  in 
Fig.  8.  It  represents  a  very  ingenious  method  of  placing  the 
ground  wire  above  the  line  conductors  without  sacrificing  pole 
height  in  order  to  secure  proper  clearance  and  with  the  offsetting 


TYPES  OF  CONSTRUCTION 


29 


of  the  top  insulator  gives  a  balanced  loading  of  the  pole.  Another 
clever  pole  top  arrangement  is  that  of  the  Consumers  Power 
Company,  as  designed  by  H.  M.  Byllesby  &  Co.  This  construc- 
tion, which  is  illustrated  in  Fig.  9,  has  been  termed  the  "  wish- 
bone" arm  arrangement.  The  arm  equipment  and  the  ground- 


__J___ 

B-B  Telephone  Wire  to  Ground  PI 
to  be  fastened  here  and  8fcpled  to 


Top  of  Pole  to  be  7  rthin. 


Pole  fo  be  Adxed  to  ;ive  Flat  Bearing  Surface 


No.  3024 
ICTnsulator 
Lee  Insulator  Pins 

Bolt  C>/long 


FIG.  8. — Southern  Power  Company's  standard  wooden  pole  construction. 

wire  bayonet  are  of  3  1/2  in.  X3  1/2  in.  Xo/16-in.  angle  iron. 
The  arrangement  brings  the  top  insulator  above  the  roof  of  the 
pole,  and  requires  less  room  on  a  support  than  any  other  con- 
struction yet  devised  to  carry  a  ground  wire  above  the  line 
conductors.  While  this  pole  top  design  is  very  efficient,  the  use 
of  steel  on  a  wooden  structure  is  incongruous.  The  cost  of  the 
construction  with  the  spans  employed,  about  125  ft.,  must  be 
very  close  to  that  of  steel  pole  or  steel  tower  work  in  economical 
spans. 


30 


TRANSMISSION  LINE  CONSTRUCTION 


Single-circuit  construction  is  always  preferable  where  it  is 
possible  to  build  two  separate  lines  situated  from  30  ft.  to  50  ft. 
apart  instead  of  carrying  both  circuits  on  one  pole.  The  best 
method  of  all  is  to  bring  the  two  single  circuits  in  by  as  widely 
diverging  routes  as  practicable,  but  in  this  case  it  is  not  possible 
to  use  cut-over  switches  to  gain  the  fullest  advantage  from  sec- 
tionalizing  switches  if  they  are  installed. 

Where  double-circuit  lines  are  to  be  built,  the  arrangement  of 


FIG.  9. — "Wish-bone"  cross-arm  arrangement. 


the  pole  top  for  most  cases  is  that  shown  in  Fig.  10  or  Fig.  11. 
In  Fig.  10  it  will  be  noted  that  the  long  arm  is  at  the  top,  whereas 
in  Fig.  11  it  is  at  the  bottom.  Where  the  long  arm  is  above, 
repairs  may  be  made  with  greater  safety  because  more  clearance 
is  provided  for  a  man  to  work  on  the  dead  circuit  while  the  other 
one  is  alive;  on  the  other  hand,  with  four  wires  at  the  top,  the 
pole  is  subjected  to  somewhat  greater  strain.  However,  the 
balance  of  advantage  favors  the  installation  of  the  long  cross- 
arm  above.  These  arrangements  are  good  only  up  to  about 


TYPES  OF  CONSTRUCTION 


o  J 


\ 


FIG.  10. — Double  circuit  pole  top  for  voltages  up  to  44,000  volts. 


a  J  a 


t t 


t 


V- 

FIG.  11. — Double  circuit  pole  top  for  voltages  up  to  44,000  volts. 


32 


TRANSMISSION  LINE  CONSTRUCTION 


40,000  volts  on  account  of  the  long  arm  required  for  voltages 
higher  than  that. 

Another  design  that  is  mechanically  better  than  either  of  the 
foregoing,  and  one  that  is  used  in  carrying  double-circuit  lines 
at  the  higher  voltages,  is  the  triple  cross-arm  scheme  shown  in 
Fig.  12.  This  type  of  pole  top  is  open  to  the  objection  that  it 
does  not  give  as  safe  clearance  for  a  man  working  on  one  circuit 
with  the  other  alive,  as  the  two-arm  construction  does. 

The  spans  for  double-circuit 
lines  are  generally  about  the  same 
as  those  for  single-circuit  con- 
struction up  to  where  the  line  con- 
ductors are  No.  1  or  so;  from  there 
on  the  spans  are  cut  down  as  may 
be  dictated  by  the  size  of  the 
conductors,  by  climatic  conditions 
and  very  often  by  financial  cir- 
cumstances. 

While  it  has  been  the  standard 
Eastern  and  Middle  Western  prac- 
tice to  build  with  the  spans  here- 
inbefore noted,  the  Western  lines, 
especially  near  the  Pacific  Coast 
have  used  wooden  poles  to  carry 
much  longer  sections.  Thus  Mr. 
Baum  mentioned  in  his  paper  on 
11  Transmission  Economics"  in  the 
1907  Transactions  American  In- 
stitute of  Electrical  Engineers 
that  the  California  Gas  &  Electric 
Corporation  has  used  single 
wooden  poles  with  single  arm  and 
insulator  construction  to  carry 
spans  up  to  500  ft.  on  straight 
line;  also  that  the  same  line 


FIG.  12. — Double  circuit  pole  top, 
— voltages  over  44,000  volts. 


equipped  with  double  arm  and  plate  construction,  but  with 
only  one  insulator  per  phase,  has  been  used  for  spans  rang- 
ing from  500  ft.  to  700  ft.,  and  with  two  insulators  per  wire, 
for  700  ft.  to  900  ft.  Of  course,  these  spans  are  carried  on 
comparatively  short  poles  located  on  high  points  in  hilly 
country  where  it  is  possible  safely  to  give  the  conductors 


TYPES  OF  CONSTRUCTION 


33 


the  heavy  sag  required  because  of  the  natural  clearance  due 
to  the  contour  of  the  ground.  Again,  with  the  short  poles  in 
service,  the  moment  of  the  transverse  stresses  is  correspond- 
ingly reduced.  Clearance  between  conductors  is  provided  by 
a  spacing  of  7  ft.  for  spans  up  to  500  ft. ,9  ft.  for  500-ft.  to  700- 
ft.  sections,  and  11  ft.  for  700-ft.  to  900-ft.  spans.  Besides  this 
particular  installation,  there  are  several  other  notable  lines  on  the 


FIG.  13. — Madison  River  Power  Company's  long  span  wooden  pole  line. 

Pacific  Coast  where  the  spacing  has  been  much  greater  than  it 
would  be  in  the  East.  The  absence  of  sleet  in  the  Far  West, 
except  in  a  few  isolated  sections,  is  naturally  responsible  for  the 
good  showing  made  by  this  long-span  construction. 

A  recent  example  of  medium  long-span  work  on  wooden  poles, 
is  that  of  the  Madison  River  Power  Company,  whose  line  has 
been  in  service  since  November,  1910,  with  a  very  clear  operating 
record.  This  line  is  built  with  a  standard  span  of  300  ft.  using 
8-in.  top,  45-ft.  and  50-ft.  Idaho  cedars.  The  pole  top  layout  is 


34  TRANSMISSION  LINE  CONSTRUCTION 

shown  in  Fig.  13.  The  maximum  span  with  standard  con- 
struction is  834  ft.,  with  many  in  the  neighborhood  of  500  ft. 
The  line  wires  are  medium  hard  drawn  copper  strand  made  up  of 
three  No.  8  B.  &  S.,  with  a  three-strand  Siemens-Martin  ground 
wire  of  about  the  same  weight  as  the  line  conductors.  The 
insulators  are  of  the  suspension  type  with  three  units,  operating 
under  50,000  volts.  On  this  line,  the  height  of  the  pole  alone  for 
the  long  spans  carried,  gives  the  necessary  clearance  to  ground. 
While  this  type  of  construction  lacks  the  high  initial  factor  of 
safety  of  the  ordinary  wooden  pole  line,  it  has  been  very  'satis- 
factory. In  the  writer's  opinion,  steel  or  possibly  concrete  poles, 
with  medium  length  spans  of  say  from  250  ft.  to  350  ft.,  will  be 
much  used  in  the  future. 

Throughout  the  continent,  where  added  strength  or  rigidity  is 
necessary,  as  at  river  crossings,  in  swamp  and  bottom  land  con- 
struction, and  also  for  a  standard  in  medium  or  long-span  work, 
we  find  much  utilized  the  A-  or  H-frame  construction,  which  is 
shown  respectively  in  Figs.  14  and  15.  These  frames  are  made 
up  of  two  poles  arranged  in  the  shape  of  the  letter  from  which 
they  derive  their  name.  The  A-frame  as  generally  proportioned, 
has  the  strength  of  two  poles  along  the  line  and  about  four  across 
the  line.  In  addition  to  its  advantage  in  strength  over  single 
poles,  the  A-frame  makes  a  very  good,  rigid  structure  in  soft 
ground,  where  by  doubling  the  length  of  the  spans  from,  say  125 
ft.  to  250  ft.,  it  gives  a  very  economical  fixture.  However,  it 
requires  much  more  room  than  a  single  pole  line.  This  last  fact, 
in  connection  with  the  higher  labor  cost  of  framing  and  setting, 
does  not  compensate  enough  for  the  increase  in  strength  over 
ordinary  single  pole  construction,  to  make  the  use  of  A-frames 
generally  justifiable  as  a  standard  type  of  construction.  Wooden 
A-frame  construction  was  used  to  quite  an  extent  in  some 
of  the  Ontario  Power  Company's  work,  and  for  several  other 
installations. 

H-frames  are  used  under  about  the  same  circumstances  as  A- 
frames.  Several  lines  have  been  built  with  this  type  of  structure 
set  from  250  ft.  to  300  ft.  apart.  Without  extra  braces,  however, 
they  are  not  as  rigid  as  A-frames.  H-frames  have  been  used 
quite  extensively  on  one  system  in  Utah,  the  one  long  arm  being 
far  enough  down  from  the  top  of  the  poles  to  allow  clearance  for 
two  ground  wires,  one  at  the  peak  of  each  pole. 

For  special  purposes,  there  has  been  employed  a  great  variety 


TYPES  OF  CONSTRUCTION 


35 


of  wooden  pole  structures  such  as  double  A-frames  and  H-frames, 
three-pole  structures,  etc. 

Steel  poles  are  now  being  used  to  a  greatly  increasing  extent. 
For  the  average  voltages  and  conductor  sizes,  they  give  a  more 
economical  construction  than  straight  tower  lines,  due  to  the 
lower  right-of-way  and  labor  costs  possible.  In  Europe  the  use 
of  steel  poles  not  only  for  transmission  work,  but  even  for  tele- 
graph and  telephone  work  is  very  common,  and  steel  construc- 


f 


FIG.  14. — A-frame. 


FIG.   15. — H-frame. 


tion  is  also  somewhat  used  for  distribution  work  in  many  cities. 
In  America,  wooden  pole  construction  has  in  the  past  had  the 
advantage  of  a  much  lower  first  cost,  and  on  this  account  has 
been  widely  used  in  developments  where  the  main  consideration 
of  the  promoters  was  for  something  cheap.  (Now,  however, 
steel  construction  is  rapidly  coming  into  its  own  in  consideration 
of  its  fair  cost,  greater  reliability  and  much  lower  maintenance 
charges. 

The  latticed  riveted  type  of  pole  structure  is  probably  the  one 


36  TRANSMISSION  LINE  CONSTRUCTION 


FIG.  16. — Steel  pole  used  by  New  York  Central  &  Hudson  River  Railroad. 


TYPES  OF  CONSTRUCTION 


37 


that  has  been  used  to  the  greatest  extent,  particularly  abroad. 
It  is  ordinarily  built  up  of  four  main  angle-iron  corner  members, 
laced  with  angle  iron  or  flat  bars,  the  whole  being  assembled  and 
riveted  in  the  shop  in  one  piece  for  ordinary  lengths,  and  in  two  or 


FIG.  17. — Sanitary  district — steel-pole  construction. 

more  sections  for  the  field  splicing  of  high  poles.  The  section 
usually  is  square  with  a  uniform  taper  from  top  to  bottom,  as 
may  be  demanded  by  conditions  of  loading.  In  ordinary  work 


38 


TRANSMISSION  LINE  CONSTRUCTION 


single   lacing  is  ample.     The  cross-arms  are  generally  of  steel 
although  wooden  arms  have  sometimes  been  used. 

While  latticed  riveted  poles  have  not  been  used  so  widely  in 
the  United  States  as  in  Europe,  there  are  a  few  good  examples  of 
this  kind  of  construction  in  this  country.  Among  them  are  the 
New  York  Central  &  Hudson  River  Railroad's  electric  zone,  the 
Long  Island  Railroad,  and  the  Sanitary  District  lines,  with  many 


FIGS.  18  and  19. — Lauckhammer  steel  poles. 


L  100-100-10 


isolated  cases  where  short  stretches  of  line  have  been  built  with 
latticed  poles.  The  first-mentioned  line,  shown  in  Fig.  16,  used 
wooden  cross-arms  and  the  last  named,  illustrated  in  Fig.  17,  has 
built-up  steel  arms. 

Europe  has  many  great  systems  using  latticed  steel  poles.  In 
the  earlier  work  straight  four-post  riveted  poles,  much  like  those 
just  described,  were  used  throughout  the  entire  line.  More 


TYPES  OF  CONSTRUCTION 


39 


Channels 


recently,  the  lines  have  been  constructed  on  the  flexible  system. 
In  a  typical  example,  the  200-  ft.  or  300-ft.  spans  have  light  poles 
built  up  of  two  channel  posts  laced  with  light  angle  iron,  with 
heavy  four-post  latticed  angle  poles  at  uniform  intervals.  The 
general  tendency  in  Europe  has  been  to  use  a  bracket  support 
instead  of  cross-arms  for  the  insulators.  Each  bracket  holds  one 
insulator.  It  is  also  noted  in  many  instances  that  where  arms  are 
used,  the  conductors  are  so  arranged  that 
the  bottom  of  the  equilateral  triangle 
formed  is  not  horizontal.  It  also  appears 
to  be  the  practice  to  carry  more  than  one 
circuit  on  a  pole. 

In  the  north  of  Italy,  under  the  guid- 
ance of  Mr.  Semenza,  in  Switzerland  and 
in  Germany,  a  great  deal  of  latticed  pole 
construction  has  been  built.  Fig.  18  shdws 
the  anchor,  and  Fig.  19  the  intermediate 
poles  for  the  recent  Lauckhammer  line  in 
Germany  the  first  in  Europe  to  operate  at 
110,000  volts.  The  design  of  its  structures 
is  typical  of  those  employed  in  Europe  for 
latticed  pole  construction,  except  that 
cross-arms  have  not  been  employed  to  as 
great  an  extent  as  in  America. 

While  the  latticed  pole  has  been  much 
favored  for  transmission  work,  tubular  poles 
and  various  patented  types  have  also  been 
put  forth.  Of  the  latter  designs  the  dia- 
mond and  the  tripartite  are  the  most 
prominent.  F,G.  20.-Diamond  pole. 

The  tubular  pole  is  not  economical  for  transmission  work. 
It  has  not  been  used  much  for  that  purpose  in  this  country,  al- 
though it  has  been  given  more  favorable  consideration  in  Europe. 

The  diamond  type  pole,  which  like  the  tubular  is  best  adapted 
to  electric  railway  trolley  work,  is  made  of  two  sheet  steel  V- 
shaped  troughs  with  flanged  edges,  driven  one  within  the  other 
longitudinally,  as  shown  in  Fig.  20,  which  also  shows  a  typical 
cross-arm  with  method  of  attachment.  The  taper  of  the  pole  and 
the  thickness  of  the  metal  vary  with  the  conditions  of  loading 
imposed.  The  pole  is  set  so  that  the  line  of  strain  is  taken  on 
the  diagonal  passing  through  its  joints.  Strength  and  stiffness 


Gtamad 


40  TRANSMISSION  LINE  CONSTRUCTION 

are  added  by  the  extra  metal  at  the  joints.  This  type  of  pole 
is  lighter  than  the  tubular  pole,  but  it  has  the  same  great  disad- 
vantage, namely,  that  it  is  impossible  to  get  at  and  protect  all 
of  the  surface  most  subject  to  corrosion. 

The  other  patented  pole,  the  tripartite,  is  practically  a  struc- 
tural pole  with  bolted  connections.  It  is  composed  of  three  U- 
section  members  arranged  in  the  shape  of  an  equilateral  triangle, 
and  bound  together  with  malleable  iron  clamps,  called  collars 
and  spreaders.  A  typical  line  built  with  this  pole  is  shown  in 
Fig.  21.  Fig.  22  shows  the  constructional  features  of  the  design. 


FIG.  21. — Tripartite  steel  pole  line. 

The  number  of  collars  and  spreaders  used,  as  well  as  the  taper 
given  the  pole,  varies  with  the  conditions  of  loading.  Thus 
almost  any  desired  combination  can  be  made  up  with  a  few 
different  weights  of  U-bar  and  a  line  of  collars  and  spreaders  of 
various  dimensions.  The  material  of  the  U-bars  is  bessemer  steel 
with  a  tensile  strength  of  100,000  Ib.  per  square  inch. 

In  general  for  transmission  line  or  any  other  purposes,  a  pole 
that  is  accessible  for  protection  from  corrosion  is  preferable  from 
a  mechanical  standpoint.  Structural  poles  of  the  three  or  four- 


TYPES  OF  CONSTRUCTION 


41 


DIMENSIONS  Or  U    SECTIONS 

M  0. 

A 

B 

C            D            E             F            O 

1  »?»'  "iL'rooT 

2 

& 

1  5/iz 

1%     2*M      "Al      25/5Z       1  'X  6 

i     5 

4 

H 

1% 

z'Ai    \lAi   uAi    \'/3i   ZKs 

4.5 

6 

Va 

6.4 

a 

^t 

Z%z  1  Hi    ^/ii    I  %: 

9 

AA 


FIG.  22. — Details — tripartite  pole. 


42 


TRANSMISSION  LINE  CONSTRUCTION 


post  riveted  types  or  similar  designs  such  as  the  tripartite,  will  be 
the  most  favored. 

In  connection  with  the  use  of  steel  poles  for  transmission  line 
work,    it   will   be   of  interest  to  quote  the  following  from  an 


FIG.  23. — Niagara-Syracuse  towers. 

editorial  in  the  Electrical  World  for  March  30,  1911 :  "We  have 
always  had  a  fondness  for  the  steel  pole  of  moderate  height  in 
transmission  line  construction.  It  is  going  to  be  used  in  the 


TYPES  OF  CONSTRUCTION 


43 


FIG.  24. — La  Crosse  Water  Power  Co.'s  tower.       FIG.  25. — Toronto-Niagara 

Power  Co  's  tower 


FIG.  26. — Connecticut  River  Power  Co.'s  tower. 


44  TRANSMISSION  LINE  CONSTRUCTION 


FIG.  27. — Southern  Power  Co. — twin  circuit  tower. 


TYPES  OF  CONSTRUCTION 


45 


future  a  great  deal  more  than  it  has  been  in  the  past  .  .  .  ." 
The  writer  believes  that  this  prophesy  will  come  true  and 
that,  following  the  lead  of  European  practice  in  this  regard, 
poles,  in  preference  to  towers,  will  be  employed  more  and 
more  for  general  work;  and  that  they  will  show  greater  econ- 
omy than  tower  construction,  especially  where  right-of-way  cost 
is  any  appreciabls  part  of  the  total. 


FIG.  28. — Sierra-San    Fran- 
cisco Power  Co.'s  tower. 


FIG.  29. — Single-circuit  tower  used  by 
the  Ontario  Hydro-electric  Power  Com- 
mission. 


Steel  tower  construction  embraces  an  almost  innumerable 
variety  of  designs  in  the  two  fundamental  systems  of  using  either 
structures  of  equal  strength  throughout  which  are  designed  to 
carry  considerable  horizontally- applied  loads  in  any  direction, 
or  of  providing  heavy  anchor  towers  which  are  located  usually  at 


46 


TRANSMISSION  LINE  CONSTRUCTION 


mile  intervals  with  intermediate  two-post  A-  or  H-frame  steel 
structures  to  resist  heavy  strains  transverse  to  the  line  but  with 
only  nominal  strength  in  a  longitudinal  direction.  These  two 
methods  may  be  designated  as  " rigid"  and  "flexible,"  and  both 
have  a  strong  following  among  engineers.  The  flexible  or 
elastic  system  is  used  to  a  very  great  extent  in  Europe.  To  the 
writer's  mind  it  appears  that  the  flexible  system  is  a  reaction 


i 


!r 


/\ 


FIG.  30. — Standard  tower  used  on  140,000  volt  line  of  Au  Sable  Power  Co. 

from  the  practice  followed  in  many  installations  of  specifying 
that  the  strength  of  a  tower  shall  be  sufficient  to  stand  the 
unbalanced  strain  due  to  the  severance  of  all  the  conductors  on 
one  side  of  the  structure  or  similar  severe  assumptions.  A 
tower  built  to  such  specifications  was  necessarily  high  priced,  and 
the  search  for  a  means  of  reducing  line  costs  has  led  to  the  other 
extreme.  However,  with  anchor  towers  at  close  enough  inter- 
vals and  with  sufficiently  heavy  ground  wires,  there  is  no  reason 
why  the  flexible  system  will  not  work  out  satisfactorily. 

The  typical  tower  for  single-circuit  rigid  construction,  which  is 


TYPES  OF  CONSTRUCTION 


47 


illustrated  in  Fig.  23,  has  no  ground  wire,  is  49  ft.  from  lowest 
conductor  to  ground  and  carries  the  line  in  550-ft.  spans,  stand- 
ard spacing.  An  example  of  a  single-circuit  tower  with  provision 
for  a  ground  wire  is  shown  in  Fig.  24.  This  structure  is  built 
to  carry  three  No.  2  copper  strand  conductors,  one  ground  wire 
of  similar  weight,  and  two  No.  5  B.  &  S.  hard-drawn  copper 
telephone  wires  in  480-ft.  spans  or  eleven  per  mile. 


FIG.  31. — Type  of  tower  used  by  Central  Colorado  Power  Co. 

Figure  25  illustrates  a  good  example  of  a  tower  which  is  de- 
signed to  carry  two  circuits  without  ground  wire,  while  Fig.  26 
shows  a  similar  two-circuit  structure  with  a  ground- wire  support 
provided.  These  two  types  have  been  widely  used  with  uni- 
form success.  A  type  of  double-circuit  structure,  however,  that 
isolates  the  two  circuits  to  a  greater  extent,  is  that  shown  in 


48  TRANSMISSION  LINE  CONSTRUCTION 


FIG.  32. — Southern  Power  Co. — 100,000-volt  double-circuit  construction. 


TYPES  OF  CONSTRUCTION 


49 


Fig.  27.  While  this  tower  may  not  have  much  greater  actual 
clearance  between  the  two  separate  circuits  than  may  be  provided 
for  in  the  two  designs  previously  noted,  the  separation  is  more 
effective  so  that  repairs  can  be  made  with  greater  safety.  When 
the  patrolmen  have  a  greater  sense  of  security,  they  can  make 
repairs  in  less  time,  thus  minimizing  the  time  of  shut-down. 
From  a  mechanical  standpoint,  however,  the  design  in  Fig.  27 
does  not  appear  to  be  as  economical  or  as  strong  as  the  preceding 
structures.  It  will  be  noted  that  the  last  type  of  tower  carries 
two  ground  wires,  one  at  the  peak  of  each  side. 


FIG.  33. — Ontario  Hydro-electric  Power  Co.  standard  double-circuit  tower. 

The  designs  so  far  discussed  have  been  arranged  for  pin-type 
insulators  but  the  same  main  structures,  with  cross-arms  and 
supports  adapted  to  the  suspension  type,  are  used  in  either  case. 
Designs  followed  out  in  good  practice  are  shown  in  Figs.  28,  29 
and  30.  The  type  of  cross-arm  used  in  the  single-circuit  tower 
in  Fig.  28,  etc.,  is  the  one  employed  in  most  cases,  although 
several  lines  have  been  built  where  the  conductors  are  carried  in 
a  horizontal  plane  from  one  long  arm  as  shown  in  Fig.  31. 

Two  general  methods  of  supporting  two  circuits  on  suspension 
type  insulators  are  shown  in  Figs.  32  and  33.  The  first  design 
has  often  been  preferred,  however,  for  voltages  of  100,000  volts 


50 


TRANSMISSION  LINE  CONSTRUCTION 


and  more,  because  of  the  long  cross-arming  that  is  required  to 
carry  four  conductors  in  the  same  plane  and  to  give  them  proper 
electrical  clearance;  also  the  great  torsional  moment  exerted 
with  the  long  arm  calls  for  a  heavier  structure,  although  this  is 
offset  by  the  greater  height  of  tower  which  is  necessary  where  the 
conductors  are  arranged  vertically  on  each  side. 


FIG.  34a.  FIG.  346. 

Flexible  intermediate  towers. 

In  the  flexible  system  the  anchor  towers  are  of  the  same 
general  types  as  those  that  have  been  described,  proportioned, 
of  course,  to  meet  the  greater  demands.  The  intermediate 
structure  designs  are  a  reversion  to  the  A-  and  H-frame  types 


TYPES  OF  CONSTRUCTION  51 

used  in  wooden  pole  construction.  A  good  example  of  an  A-- 
frame intermediate  tower  is  that  shown  in  Fig.  34.  Its  main 
members  are  heavy  channel  iron  with  angle-iron  girts  and 
round  rod  diagonal  bracing,  giving  a  structure  which  can  resist 
heavy  strains  in  a  direction  across  the  line  but  which  has  only 
slight  strength  in  the  opposite  direction.  This  construction  has 
economy  in  tower  weight,  but  the  greatest  saving  over  that  of  a 


FIG.  34c.  FIG.  34d. 

Intermediate  and  anchor  towers  used  in  flexible  tower  work. 

straight  rigid  construction  is  in  its  lower  assembling  and  erection 
labor  costs.  A  first  cost  very  close  to  that  of  wood  is  claimed 
for  it. 

The  H-f rame  has  not  been  much  used  commercially  for  flexible 
line  work,  the  A-frame  lending  itself  more  readily  to  the  usual 
arrangement  of  conductors. 

In  this  system  of  construction  the  anchor  towers  are  usually 


52 


TRANSMISSION  LINE  CONSTRUCTION 


specified  at  1-mile  intervals;  also  at  all  corners  and  ail  road, 
telephone,  telegraph,  transmission  line  and  railroad  crossings. 
In  reinforced  concrete  we  have  a  new  material  for  line  supports 
for  which  much  has  been  claimed.  As  yet,  however,  excepting 
for  a  few  isolated  cases  of  light  construction,  its  use  has  been 
confined  mainly  to  trolley,  telegraph,  telephone  and  city  distribu- 
tion work,  which  as  a  rule  do  not  demand  the  same  type  of 
structure  as  a  transmission  line. 


FIG.  35. — Concrete  poles  of  Oklahoma  Gas  &  Electric  Co. 

There  are  two  general  classifications  of  concrete  poles — those 
molded  horizontally  in  a  yard  or  near  the  pole  location,  and  those 
cast  vertically  in  place  like  the  column  of  a  building.  The  former 
method  is  the  only  practicable  one  for  transmission  line  work. 
The  ordinary  practice  in  this  country  has  been  to  use  a  trough 
form,  casting  the  poles  by  hand.  This  has  worked  out  well,  but 


TYPES  OF  CONSTRUCTION 


53 


is  necessarily  slow.     The  Germans,  however,  have  developed  a 
process  of  forming  hollow  poles  of  circular  section,  by  centrifugal 


FIG.  36. — Hollow  centrifugal  type  concrete  poles. 

action.  Their  form,  consisting  of  a  closed  cylinder  of  the  length 
and  taper  of  the  pole  desired,  is  revolved  in  a  lathe-like  machine 
for  from  10  toJ5  minutes,  varying  with  the  character  of  the 


54  TRANSMISSION  LINE  CONSTRUCTION 

pole.  This  method  of  manufacturing  concrete  poles  has  proved 
successful  and  is  now  being  introduced  into  this  country.  A 
plastering  machine  method  known  as  the  Siegwart  process  has 
also  been  developed  abroad. 

Figure  35  shows  a  line  using  a  typical  horizontally  molded  pole, 
and  Fig.  36  illustrates  a  line  employing  the  hollow  centrifugal 
type  for  city  distribution  work.  The  neat  appearance  presented 
by  a  concrete  pole  is  a  notable  feature  of  this  class  of  construction. 

The  cross-arm  arrangements  with  concrete  construction  are 
the  same  as  those  of  standard  wooden  pole  line  work,  excepting 
as  to  material.  Wooden  arms  have  been  used  to  quite  an  extent 
but  generally  angle  iron  is^pecified.  Concrete  arms  have  been 
experimented  with  to  some  extent  but  so  far  as  known  have  not 
been  used  commercially. 


CHAPTER  IV 

WOODEN  POLE  CONSTRUCTION 

A  wooden  pole  has  been  said  by  a  steel  pole  man  to  be  "A 
tree  trunk  converted  into  a  pole  at  the  buyer's  expense,"  and 
naturally  we  find  almost  as  many  varieties  of  pole  timbers  as 
there  are  species  of  trees.  Cedar,  however,  is  the  most  exten- 
sively used,  with  chestnut  ranking  next;  pine,  juniper,  cypress, 
oak,  tamarack,  douglas  fir,  locust,  catalpa,  red-wood  and  a  few 
others  are  used  also  in  varying  amounts,  the  first  three  being  the 
most  important. 

Cedar  is  the  most  durable  of  all  pole  timbers,  its  useful  life 
varying  with  the  section  of  the  country  where  it  is  used,  from 
ten  to  thirty  years,  and  its  lasting  qualities,  in  addition  to  its 
strength  and  lightness,  have  made  it  enormously  in  demand. 
Chestnut  does  not  have  the  long  life  of  white  cedar  and  is  much 
heavier,  but  it  is  used  to  a  very  great  extent  throughout  the 
East,  especially  the  upper  half  of  the  Atlantic  Coast  States 
where  the  supply  of  cedar  and  northern  pine  is  nearly  exhausted 
and  the  freight  rates  on  northern  and  western  poles  runs  into  big 
figures;  chestnut  is  also  used  to  quite  an  extent  throughout  the 
eastern  and  middle  section  of  the  central  group  of  states.  Yellow 
pine,  untreated  with  some  good  preservative,  is  subject  to 
extremely  rapid  decay,  having  a  life  of  only  four  or  five  years,  and 
it  is  therefore  usually  given  some  preservative  treatment  before 
being  used;  oak,  in  common  with  all  hardwoods,  does  not  last 
well,  is  expensive  and  heavy;  cypress  in  its  native  localities  is 
quite  satisfactory,  but  in  one  or  two  particular  instances,  in- 
stallations in  the  North  Central  States  have  shown  poor  life, 
in  one  case  lasting  less  than  five  years,  even  with  unusually 
heavy  poles  as  standard. 

In  general,  it  may  be  stated  that  the  best  and  most  durable 
pole  timbers  are  coniferous  woods  of  slowr  growth  in  heavy 
stands,  so  that  good  pole  trees  will  be  found  in  heavy  timber 
land  at  fairly  high  altitudes  and  where  the  soil  is  poor. 

The  time  of  cutting  is  an  important  factor  in  the  subsequent 

55 


56  TRANSMISSION  LINE  CONSTRUCTION 

life  of  a  pole.  Careful  study  and  investigation  have  shown  that 
pole  timber  felled  when  the  tree  carries  the  least  amount  of  sap 
invariably  has  longer  life  than  timber  cut  at  any  other  time;  the 
sap  is  naturally  lowest  in  the  winter  time  and  the  best  time  for 
cutting  pole  timber  is  therefore  from  November  to  April.  Ex- 
cepting for  the  large  consumers,  few  companies  make  any  note 
whatever  in  their  specifications  limiting  the  time  of  cutting, 
whereas  it  is  really  as  important  as  a  clause  specifying  the 
permissible  amount  of  butt  rot.  The  pole  should  be  trimmed, 
cut  to  length  and  peeled  immediately  after  being  felled.  It 
should  then  be  rolled  up  on  skids  in  separate  layers  and  allowed 
to  season  for  from  six  months  to  a  year. 

The  proper  seasoning  of  poles  has  also  not  been  given  the 
recognition  that  it  should  have.  Tests  by  the  Government 
Forest  Service  have  demonstrated  that  the  durability  of  a 
timber  in  itself  is  increased  by  thorough  seasoning,  and,  where 
the  brush  or  open-tank  methods  of  impregnation  are  to  be  used, 
it  is  imperative  for  securing  good  results,  that  poles  be  in  an 
air-dry  condition,  owing  to  the  low  absorption  of  the  compound 
by  unseasoned  woods.  Where  the  pressure  system  of  applying 
the  preservative  is  to  be  employed,  unseasoned  timber  can  be 
used,  but  a  great  saving  in  the  time  of  application  of  the  treat- 
ment can  be  made  if  the  timber  is  air  dry.  A  direct  saving  in 
transportation  charges  is  also  effected  by  purchasing  poles  that 
are  well  seasoned,  the  reduction  in  weight  being  from  16  per 
cent,  to  30  per  cent,  and  even  more  for  some  species,  according, 
to  government  investigations. 

To  season  poles  properly,  they  should  be  laid  out  in  single 
layers  on  sound  high  skids  and  all  underbrush,  weeds,  etc.,  cut 
away  so  that  they  will  not  be  in  contact  with  any  vegetation,  and 
especially  so  that  there  will  be  free  air  circulation  all  about  them. 
Skidding  poles  in  solid  piles  should  be  avoided  where  at  all 
possible,  as  not  only  is  the  seasoning  retarded,  but  the  timber 
is  more  susceptible  to  decay  and  to  injury  by  wood-boring 
insects.  Below  in  Table  I  are  given  results  of  an  investigation 
by  the  Government  Forest  Service  of  the  time  required  for 
proper  seasoning  of  various  species  of  poles  cut  at  different 
seasons  of  the  year.  It  will  be  noted  that,  except  in  the  case  of 
northern  cedar,  spring  and  summer-cut  poles  dry  out  more 
rapidly  than  the  fall-  and  winter-cut.  The  data  are  taken  from 
Forest  Service  Bulletin  No.  84. 


WOODEN  POLE  CONSTRUCTION 


57 


TABLE  I.— TIME   REQUIRED  FOR  POLES   CUT  AT   DIFFERENT 

PERIODS  OF  THE  YEAR  TO  SEASON  TO  APPROXIMATELY 

AIR-DRY  WEIGHT 


Time  required 

for  seasoning 

Species 

Location  of  test 

Spring-    ;  Summer- 

Autumn- 

Winter- 

cut               cut 

1           ! 

cut 

cut 

- 

Months 

Months    : 

Months 

Months 

Chestnut      

Parkton,  Md  5 

4 

8                  7 

Southern  white  cedar.  .  . 

Wilmington,  N.  C  3 

3 

8                  5 

Northern  white  cedar.... 

Escanaba,  Mich  

12 

9 

7                  6 

Western  red  cedar  

Wilmington,  Cal  {      ^ 

«5 
c(6) 

<*3 

c(7) 

«3 
c(4) 

Western  yellow  pine  

Madera  County,  Cal.  .               5 

3 

9 

6 

a  Period  of  seasoning  computated  from  time  poles  arrived  at  Wilmington  three  to  seven 
months  after  cutting. 

&  Weight  of  spring-cut  poles  at  termination  of  test,  28  Ib.  per  cubic  foot. 

c  Period  in  storage  and  in  transit,  during  which  time  little  seasoning  took  place. 

Too  rapid  seasoning,  however,  may  result  in  injurious  checking 
of  the  timber  which  not  only  increases  the  area  presented  for 
the  entrance  of  fungi  and  insects,  etc.,  but  in  all  probability  the 
torn  wood  fibers  at  checks  are  more  susceptible  to  deterioration 
than  the  exterior  of  the  pole. 

The  life  of  untreated  poles  of  the  different  species  varies  within 
wide  limits,  depending  upon  the  locality  where  they  are  used; 
the  National  Electric  Light  Association  gives  for  the  average 
of  the  figures  secured  by  a  canvass  of  members,  the  following 
for  the  country: 

Cedar 13.5  years 

Chestnut 12.0  years 

Cypress 9.0  years 

Pine 6.5  years 

Jumper 8.5  years. 

Decay  is  given  as  the  cause  of  the  destruction  of  95  per  cent, 
of  all  poles,  with  insects  4  per  cent,  and  mechanical  abrasion 
1  per  cent. ;  in  straight  transmission  line  work,  the  last-mentioned 
cause  will  practically  disappear  and  the  percentage  of  damage 
through  insects  and  birds  may  be  increased  a  per  cent,  or  two. 
In  some  sections  of  the  country  much  trouble  has  been  experi- 
enced with  wood-boring  insects,  and  in  others  woodpeckers 
have  destroyed  many  poles. 

According   to   the   statistics   compiled   by   the    Government 


58  TRANSMISSION  LINE  CONSTRUCTION 

Census  Bureau,  while  the  total  number  of  poles  purchased  by  all 
pole  users  in  the  last  four  years  has  shown  a  steady  increase  and 
while  more  cedars  have  been  used  than  all  others  combined,  the 
proportion  of  cedars  to  the  total  is  diminishing  yearly:  in  1907 
the  percentage  of  cedars  to  the  total  was  64.2  per  cent.;  in  1908, 
67.7  per  cent.;  in  1909,  65.3  per  cent,  and  in  1910,  62.8  per  cent. 
Of  the  total  number  .of  poles  used  by  electric  railways  and 
light  and  power  companies  in  1910,  almost  30  per  cent,  was  given 
some  sort  of  preservative  treatment.  From  the  statistics  we  may 
draw  the  conclusion  that  with  the  increase  in  the  cost  of  cedars, 
not  to  consider  the  exhaustion  of  the  supply,  we  are  finding  it 
more  economical  to  buy  a  pole  of  lower  inherent  life  and  to 
increase  its  period  of  usefulness  by  applying  to  it  some  preserva- 
tive process. 

Decay  in  timber  consists  in  the  destruction  of  the  wood  tissues 
by  low  forms  of  plant  life,  fungi,  requiring  heat  and  moisture 
for  development;  to  prevent  fungous  growth  in  poles  which  are 
set  in  contact  with  the  soil  or  with  hot,  damp  air,  the  wood  cells, 
as  far  as  is  possible,  are  rendered  antiseptic  by  the  application  of 
various  oils  or  chemical  solutions. 

There  are  a  variety  of  preservative  processes  that  have  been 
used  in  an  effort  to  stay  the  progress  of  decay,  some  of  the  best 
known  being  creosoting,  kyanizing,  burnetizing,  copper  sulphate 
solutions  and  tarring.  Kyanizing  consists  in  the  use  of  mercuric 
chloride  solutions  and  burnetizing,  of  zinc  chloride  solutions. 
There  are  also  a  number  of  preservative  compounds  on  the 
market  sold  under  various  trade  names,  most  of  which  have 
more  or  less  of  the  characteristics  of  creosote;  these  have  been 
used  mainly  in  giving  brush  treatments  and  have,  when  applied 
with  judgment,  given  results  amply  justifying  their  use.  In 
general  practice  in  this  country  the  use  of  creosote  has  taken 
precedence  over  that  of  mineral  salts,  and  it  is  considered  the 
most  efficient/and  economical,  the  longer  service  of  creosoted 
poles  offsetting  the  greater  first  cost  of  the  treatment.  Mineral 
salts  show  a  tendency  to  leach  out,  although  this  characteristic 
is  reduced  to  some  extent  when  proper  seasoning  or  aging 
follows  the  'treatment.  The  use  of  mineral  salts,  especially 
copper  sulphate,  appears  to  be  preferred  in  some  parts  of  Europe. 
The,  Government  Forest  Service  has  carried  out  extensive 
investigations  of  the  various  processes  of  timber  preservation 
under  widely  varying  conditions  and  with  different  species  of 


WOODEN  POLE  CONSTRUCTION  59 

timber,  seeking  the  method  that  appeared  to  give  a  maximum 
efficiency  with  a  minimum  relative  cost;  the  published  reports 
to  date  favor  coal-tar  creosote  as  the  preservative  most  nearly  ful- 
filling these  requirements  for  pole  use,  preferably  applied  by  the 
two-bath  open  tank  process,  or  the  pressure  tank  method, 
depending  upon  local  conditions. 

There  are  three  general  methods  of  applying  creosote  treat- 
ment— the  first  usually  termed  the  brujdj  Aethod,  the  second, 
the  open  tank,  and  the  third,  the  pressure_j|rocess ;  the  latter  two 
methods  are  not  necessarily  confined  to  the  use  of  creosote  as 
the  preservative,  being  also  employed  with  variations  as  neces- 
sary, for  mineral  salts. 

The  brush  method  consists  in  pointing  the  butt  of  the  pole, 
usually  from  a  point  about  2  ft.  up  to  a  point  about  8  ft.  up — 
though  often  only  a  narrow  belt  1  ft.  above  and  1  ft.  below  the 
ground  line  is  covered — with  two  coats  of  coal-tar  creosote  at 
about  200°  to  220°  F.  As  a  general  thing  two  coats  applied 
twenty-four  hours  apart  have  been  most  satisfactory  though  in 
some  cases  only  one,  and  in  others  three,  coats  have  been  tried. 
For  the  brush  method  several  of  the  proprietary  compounds, 
those  containing  a  large  percentage  of  the  heavier  oils,  have 
given  very  good  results,  often  better  than  the  regular  creosote 
as  used  for  treatment  in  general. 

Only  poles  that  are  well  air  seasoned  should  be  treated  and  the 
work  should  not  be  carried  on  following  after  a  rain  storm,  until 
the  poles  are  thoroughly  dried  out  again;  it  is  also  obvious  that 
efficient  work  cannot  very  well  be  done  in  cold  weather.  Great 
care  should  be  taken  to  remove  all  bits  of  the  inner  bark  adhering 
to  the  surface  of  the  pole  as  they  will  prevent  the  absorption  of 
the  preservative  by  the  timber  itself  and  besides  that,  they  will 
drop  off  later,  and  so  expose  portions  of  a  supposedly  treated 
surface  to  the  attack  of  decay.  Another  point  to  be  especially 
noted  in  applying  the  brush  treatment  is  that  of  carefully  working 
the  preservative  into  all  season  checks,  scars,  etc. 

The  brush  method  is  the  cheapest  process  for  the  application 
of  creosote  as  a  preservative,  the  work  being  easily  carried  on 
with  the  poles  on  skids  in  the  yard.  It  involves  only  the  use  of  a 
small  quantity  of  the  oil,  and  requires  no  investment  for  a 
treating  plant. 

The  penetration  obtained  varies,  of  course,  with  the  kind  of 
timber,  government  experiments  showing  for  two-coat  applica- 


60  TRANSMISSION  LINE  CONSTRUCTION 

tions  on  well-seasoned  poles,  1/16  in.  as  an  average  for  northern 
white  cedar,  1/8  in.  for  western  red  cedar,  1/8  in.  for  western 
yellow  pine  and  about  1/16  in.  for  chestnut;  the  northern  cedar 
poles  were  treated  in  cold  weather  and  the  penetration  is  lower 
than  it  would  probably  have  been  under  more  favorable  condi- 
tions; the  penetration  for  chestnut  given  above  is  calculated  from 
data  giving  the  total  absorption,  the  information  not  being  given 
direct. 

One  of  the  large  telegraph  companies  has  adopted  a  method 
of  pouring  the  oil  over  the  surface  of  the  pole  from  specially 
shaped  vessels,  instead  of  applying  it  with  brushes,  owing  to  the 
rapid  destruction  of  brushes  from  the  action  of  the  oil.  This 
method  has  the  advantage  of  working  or  carrying  the  oil  into  the 
checks  in  better  shape  but  is  is  doubtful  if  as  good  penetration 
can  be  secured  in  this  manner  and  the  leakage  and  spillage  is 
very  likely  to  be  greater.  The  spraying  method,  which  has 
been  experimented  with  appears  also  to  be  subject  to  these 
disadvantages. 

In  general,  we  may  say  for  the  biush  method  of  applying 
creosote  or  some  of  the  kindred  patented  preservatives,  that  it  is 
the  simplest  for  use  where  only  a  small  number  of  poles  are  to  be 
treated.  Butt  treatment  made  in  this  way  affords  sufficient 
protection  to  warrant  the  expenditure  as  a  good  business  policy. 
The  weak  point  of  this  process  is  in  its  penetration  being  so 
slight  that  bruises  or  abrasions  cut  through  the  treated  wood  and 
lay  bare  the  unprotected  portions. 

The  Forest  Service  estimates  that  the  increase  in  life  of  poles 
treated  in  this  manner  with  creosote  is  from  two  to  three  years, 
and  results  attained  in  some  localities  tend  to  show  that  the 
addition  to  their  serviceable  life  will  be  even  higher  than  this, 
probably  three  to  four  years. 

The  cost  of  a  two-coat  brush  treatment  with  creosote  as  given 
by  the  Forest  Service  is  from  15  cents  to  20  cents  per  pole  in 
the  East  and  from  20  cents  to  30  cents  in  the  West,  based  upon 
tests  on7-in.  top,30-ft.  poles  mainly,  with  the  application  extend- 
ing from  the  2-ft.  to  the  8-ft.  points  on  the  butt,  a  space  of  6  ft. 
being  covered.  Where  the  oil  is  purchased  in  small  quantities 
also,  the  cost  per  pole  may  exceed  that  given  above;  from  1/2 
gallon  to  1  gallon  per  pole  will  be  required  for  the  treatment  of  a 
30-ft.  pole  as  outlined,  depending  upon  the  kind  of  timber  and 
its  degree  of  seasoning. 


\VOODEN  POLE  CONSTRUCTION  61 

However,  where  any  great  number  of  poles  is  to  be  treated, 
the  use  of  either  the  open  tank  or  the  pressure  method  is  advis- 
able, the  preferable  one  depending  upon  climatic  conditions  and 
timber  species. 

The  open  tank  method  of  creosoting  consists  in  subjecting  the 
poles  first  to  a  hot  bath  of  oil  for  from  three  to  six  hours  and  then 
to  a  cold  one  for  from  two  to  four  hours;  the  temperature  of  the 
hot  bath  is  maintained  at  about  215°  to  220°  F.,  and  that  of  the 
cold  one  at  about  110°  to  150°  F.,  the  most  suitable  temperatures 
and  the  length  of  time  required  for  the  treatment  varying  greatly 
with  the  condition  of  the  timber. 

The  theory  of  the  open  tank  method  is  that  in  the  hot  bath  the 
heat  of  the  oil  " boils  out"  the  moisture  and  the  air  in  the  wood 
cells  and  in  the  walls  of  the  wood  cells,  expanding  such  air  and 
moisture  as  is  not  driven  off,  then,  when  the  bath  cools  or  the 
hot  bath  is  replaced  by  a  cold  bath,  this  remaining  air  and 
moisture  contracts  and  condenses  and  tends  to  produce  a 
vacuum,  drawing  the  preservative  into  the  wood  cells;  the  pene- 
tration is  also  assisted  by  capillary  action.  The  main  function 
of  the  hot  bath  therefore  is  to  prepare  the  timber  for  absorption 
of  the  preservative,  and  the  actual  penetration  of  the  oil  takes 
place  when  the  hot  bath  cools  or  a  cold  bath  is  introduced. 

There  are  three  general  methods  of  applying  the  open  tank 
process  with  reference  to  the  way  in  which  the  two  baths  are 
handled;  the  temperature  of  the  oil  may  be  maintained  at  the 
"hot"  temperature  for  the  required  number  of  hours  and  then 
the  heating  may  be  discontinued  and  thebil  allowed  to  cool  as  it 
is,  using  the  same  batch  of  oil  for  both  baths,  or  the  poles  may  be 
moved  from  the  hot-bath  tank  to  another  containing  cool  oil,  or 
again,  the  hot  bath  may  be  drained  off  and  the  cool  bath  pumped 
in.  The  first  method  requires  too  much  time  for  commercial 
treating,  but. can  be  used  economically  where  a  small  company 
wishes  to  treat  its  own  poles  in  small  batches  at  intermittent 
periods;  the  second  method  involves  too  much  handling  of  the 
poles  with  an  accompanying  loss  of  the  preservative  through 
dripping,  but  allows  a  lower  investment  in  plant;  the  third  is  the 
most  economical  and  satisfactory  method  where  the  plant  can  be 
properly  arranged. 

The  depth  of  penetration  obtained  by  the  use  of  the  open  tank 
method  varies  of  course  with  the  timber,  its  species,  rate  of 
growing,  seasoning,  etc.,  the  following  being  average  results 


62 


TRANSMISSION  LINE  CONSTRUCTION 


obtained  in  the  Forest  Service  experiments:  Chestnut  0.3  in., 
northern  white  cedar  0.5  in.,  western  red  cedar  0.8  in.,  western 
yellow  pine  3.1  in. /and  lodgepole  pine  1.0  in.  In  the  open  tank, 
method  it  will  be  noted  that  the  penetration  is  very  much 
greater  than  with  the  brush  method,  but  that  it  does  not  extend 
much  beyond  the  depth  of  the  sap-wood. 

In  the  experimental  use  of  the  open  tank  method  by  the  Forest 
Service,  a  shallow  tank  with  a  sloping  bottom  was  first  used,  the 
angle  of  the  slope  and  the  depth  of  the  tank  being  such  that 
about  7  ft.  or  8  ft.  of  the  butts  of  the  poles  were  submerged  without 
having  to  raise  the  top  of  the  poles  more  than  a  relatively  small 
distance  in  the  air;  the  tank  was  sunk  into  the  ground  so  that  the 
top  was  but  a  little  above  ground  level,  with  arrangements  made 
for  a  fire  underneath.  The  poles  were  snaked  with  a  team  up 
alongside  of  the  tank,  then  rolled  into  position  over  the  edge,  and 
the  butts  immersed  by  raising  the  tops  with  a  pair  of  blocks  and 
suspending  them  with  a  sling  from  a  timber  rack  overhead. 
While  this  makes  a  cheap  outfit  where  only  a  small  number  of 
poles  is  to  be  treated,  the  method  involves  the  use  of  a  large  quan- 
tity of  oil  in  proportion  to  the  number  of  poles  treated,  it  is  slow 


Frame  from  which  Poles 

are  Supported  with 

Light  Blocks- 


Ash  i>i 


FIG.  37. — Small  open  tank  treating  plant. 


and  the  loss  of  the  oil  by  evaporation  is  high,  owing  to  the  broad 
surface  exposed;  as  in  this  method  the  cold  bath  is  obtained  by 
allowing  the  hot  bath  to  cool,  usually  only  one  charge  a  day  can 
be  treated. 

As  roughly  outlined  in  Fig.  37,  a  plant  of  this  type  with  a  capac- 
ity of  about  twelve  to  fifteen  7-in.  top,  40-ft.  poles,  butt-treated  to 
a  height  of  about  8  ft.,  can  be  built  for  about  $600  to  $700,  not 
including  rigging  and  tackle  for  handling  the  poles;  and  the  cost 
of  treating  with  creosote,  a  40-ft.  pole  as  described  above,  is 


WOODEN  POLE  CONSTRUCTION 


63 


estimated  to  be  from  $1.15  to  $1.35,  including  fixed  charges  on 

plant  and  oil  stock,  labor,  fuel  and  oil  costs,  but  not  any  charges 

for  holding  poles  for  seasoning  either  before  or  after  treatment. 

In  its  experimental  work  the  Government  later  on  used  an 


FIG.  38. — Open  tank  and  ginpole  used  in  experimental  pole  treatments. 

upright  cylindrical  tank,  7  ft.  in  diameter  and  8  ft.  deep  built  of 
1/4-in.  plate,  the  creosote  being  heated  by  means  of  an  oil 
burner  located  underneath  the  tank,  and  the  poles  being  handled 
with  a  derrick;  a  cut  of  this  tank  is  shown  in  Fig.  38.  For  com- 


64 


TRANSMISSION  LINE  CONSTRUCTION 


mercial  purposes,  the  Forest  Service  estimates  that  for  from 
$1000  to  $1200,  a  plant  along  similar  lines,  equipped  with  a  steam 
boiler  for  heating  and  for  operating  a  steam  pump,  electric  hoist 
for  derrick,  steam  pump  for  changing  oil  baths  and  an  oil-storage 
tank  of  one  car-load  capacity,  may  be  installed.  The  capacity 
of  the  treating  tank  is  twenty  poles  per  charge,  based  upon  8-in. 


FIG.  39. — Commercial — open  tank  treating  plant. 

top,  40-ft.  western  red  cedars  and  yellow  pine  poles  and,  being 
equipped  for  applying  the  cold  bath  by  change  of  oil,  two  charges 
a  day  can  be  treated. 
For  economical  operation  as  a  commercial  plant,  however,  the 


WOODEN  POLE  CONSTRUCTION  65 

Forest  Service  has  designed  the  plant  shown  in  Fig.  39.  This  plant 
is  equipped  with  two  treating  tanks,  each  7  ft. X 9  ft.  X9  1/2  ft. 
deep  with  an  estimated  capacity  each  of  thirty  8-in.  top,  40-ft. 
western  cedar  or  yellow  pine  poles,  or,  figuring  on  two  charges  per 
tank  a  day,  a  total  capacity  of  120  poles  per  operating  day. 
Arranged  as  it  is,  with  two  storage  and  measuring  tanks  and  a 
receiving  tank,  the  cost  of  the  handling  and  the  heating  of  the  oil 
can  be  reduced  to  a  minimum,  as  well  as  the  time  required  for  the 
cycle  of  operations;  a  50-h.p.  boiler  will  be  required  for  power 
and  heating. 

The  cost  of  this  tank  is  estimated  to  be  between  $4000  and 
$5000  complete  erected,  and  the  cost  of  treatment  per  pole, 
including  all  labor,  fuel  and  fixed  charges  of  the  plant,  but  not 
the  preservative  itself,  is  estimated  at  $0.422,  basing  the  estimate 
upon  a  yearly  plant  output  of  30,000  poles;  the  detail  figures  of 
this  estimate  are  given  below. 

Labor  per  Diem 

1  Yard  foreman $4 . 00 

1  Plant  engineer 4.00 

1  Stationary  engineer 4 . 00 

2  Firemen  at  $2.50 5 .00 

5  Laborers  at  $2.00 . .  10 . 00 


Total $27.00 

Labor  charge  per  pole $0 . 225 

Fuel  per  Diem 
2  Tons  of  coal  at  $4.00 . .  $8 . 00 


Total $8.00 

Fuel  charge  per  pole $0 . 067 

Maintenance  per  Annum 

Depreciation  and  repairs $500 . 00 

Interest  on  investment  in  plant  and  oil 400.00 


Total $900.00 

Maintenance  charges  per  pole $0.030 

Interest  charges  per  pole,  seasoning $0 . 100 


Total  treatment  cost,  not  including  pre- 
servative    $0 . 422 

It  will  be  noted  that  the  labor  charge  is  a  little  more  than  half 
of  the  total  cost  of  treatment,  and  also  that  the  wage  scale  is 

5 


TRANSMISSION  LINE  CONSTRUCTION 


higher  than  will  ordinarily  obtain  outside  of  large  cities  and  in  the 
Far  West;  furthermore,  the  duties  of  the  plant  engineer  could  be 
assumed  by  the  stationary  engineer  in  addition  to  his  regular 
duties,  and  where  the  plant  is  operated  in  connection  with  a  pole 
yard,  as  appears  to  be  the  assumption  in  the  case  above  where  no 
charge  is  noted  for  the  loading  and  unloading  of  poles  from  cars, 
only  part  of  the  plant  foreman's  time  need  be  given  to  the 
routine  operation  of  the  treating  plant,  so  that  it  is  probable  that 
a  substantial  reduction  in  labor  cost  can  be  made.  Also,  if  the 
pole  yard  be  located  so  as  to  be  able  to  purchase  steam  and  use 
an  electric  hoist  and  a  motor-driven  pump,  not  only  can  a  large 
reduction  in  cost  be  made,  but  a  further  decrease  in  labor  charge 
can  be  attained  as  well. 

Based  upon  the  estimate  of  $0.422  or,  as  it  is  used  in  round 
numbers,  45  cents  per  pole  for  butt  treatment,  the  total  cost  of 
applying  the  treatment  to  poles  of  different  species  is  given  below 
in  Table  II,  which  is  the  average  of  the  results  obtained  in  the 
government  tests  in  conjunction  with  the  estimates  noted;  the 
same  is  discussed  in  detail  in  Forest  Service  Bulletin  No.  84. 

TABLE  II.— COST  OF  CREOSOTE    BUTT   TREATMENT    BY  OPEN 

TANK  METHOD 


Species 

Size  of  pole 

Amount  of  creo- 
sote applied 

Cost  of  treatment 

Top 
diam. 
in. 

length 

a 

Lb.  per 

cu.  ft, 

Lb.  per 
pole 

Preser- 
vative 

Opera- 
tion 

Total 
cost 

Chestnut  
Northern  white  cedar  
Western  yellow  pine  
Western  yellow  pine  
Western  red  cedar  
Lodgepole  pine  

7 
7 
8 
8 
8 
7 

30 
30 
40 
40 
40 
35 

25 
50 
37.5 
62.5 
39 
35 

$0.30 
.60 
.90 
1.45 
.90 
.80 

$0.45 
.45 
.45 
.45 
.45 
.45 

$0.75 
1.05 
1.35 
1.90 
1.35 
1.25 

6 
10 
6 

The  increase  in  the  life  of  pole  resultant  upon  the  use  of  creo- 
sote in  this  manner  is  as  yet  not  very  definitely  established,  but 
from  all  data  available  and  taking  into  consideration  the  life  of 
treated  ties,  the  butt  will  very  likely  outlast  the  top,  and  so  the 
ultimate  life  of  the  pole  will  be  the  serviceable  life  of  its  upper 
portion.  The  Forest  Service  believes  that  conservative  esti- 
mates for  the  total  useful  life  of  butt-treated  poles  of  the  different 
species  are  as  follows:  Chestnut,  twenty  years;  western  cedar, 


WOODEN  POLE  CONSTRUCTION  67 

twenty  years;  northern  white  cedar,  twenty-two  years;  and  in 
the  drier  western  climate,  pine,  twenty  years.  These  figures, 
especially  in  the  case  of  northern  white  cedar,  will  very  likely  be 
exceeded,  as  many  cases  are  known  of  such  pole  tops  that  have 
been  in  service  for  twenty-five  to  thirty  years;  furthermore,  it 
is  very  probable  that  in  untreated  poles,  the  rot  in  the  butt  will 
infect  the  whole  pole,  and  with  this  eliminated  to  a  great  extent 
with  a  treated  butt,  better  life  for  the  upper  portion  of  the  pole 
may  be  expected.  The  occurrence  of  infected  soil  and  its  effect 
on  pole  timber  was  clearly  established  in  Europe,  in  experiments 
on  the  use  of  copper  sulphate  as  a  preservative  for  pine,  spruce 
and  larch  poles;  the  effect  of  a  decaying  butt  on  the  upper  part  of 
a  pole  is  analogous  to  the  above. 

In  localities  in  the  South,  where  the  upper  portion  of  a  pole 
decays  almost  as  rapidly  as  the  butt,  the  whole  pole  is  subjected 
to  treatment.  The  open  tank  method  may  be  employed  for  this, 
as  well  as  for  butt  treatment  alone,  using  a  horizontal  cylin- 
drical tank  with  doors  at  each  end,  through  which  the  charge, 
loaded  upon  low  trucks,  is  handled.  However,  as  the  open  tank 
method  is  not  adapted  to  the  treatment  of  woods  which  are 
difficult  to  impregnate,  or  of  unseasoned  or  partly  seasoned 
poles,  and  furthermore  is  subject  to  a  heavy  loss  of  oil  by 
volatilization  from  the  exposed  surface  of  the  treating  tank,  and 
as  no  great  uniformity  in  the  absorption  of  the  preservative  can 
be  attained,  the  pressure  method  is  recommended  where  it  is 
necessary  to  treat  the  entire  pole.  The  cost  of  a  low-pressure 
plant  over  that  of  an  open  tank  plant  for  complete  treatment  is 
not  great,  and  considering  the  better  results  obtained,  is  advisable 
as  a  business  proposition. 

In  the  application  of  the  pressure  treatment,  we  have  the  full 
cell  and  the  partial  cell  methods  of  impregnating  timber,  the 
former  consisting  in  general,  in  displacing  the  contents  of  the 
wood  cells  with  the  oil,  and  the  latter,  in  coating  the  cell  walls. 
In  this  country  the  full  cell  method  has  been  used  mostly  for 
poles,  but  in  some  of  the  European  countries,  the  partial  cell 
treatment  by  the  Reuping  or  similar  processes,  has  been  more 
favored.  A  good  discussion  of  the  various  pressure  processes 
employed  in  the  treatment  of  timber  with  creosote  is  given  in 
the  Engineering  News  for  Oct.  14,  1909,  and  only  a  general  out- 
line of  the  method,  as  used  for  the  pressure  treatment  of  pole 
timber  by  one  of  the  largest  telephone  systems,  will  be  given  here. 


68  TRANSMISSION  LINE  CONSTRUCTION 

The  process  used  is  what  is  known  as  the  full  cell  method,  and 
the  first  step  consists  in  steaming  or  heating  the  poles  in  the 
treating  vessel,  which  is  a  horizontal  cylindrical  tank  like  that 
for  the  treatment  of  the  entire  pole  by  the  open  tank  method, 
except  that  it  is  arranged  for  sealing  so  as  to  stand  a  pressure  of 
about  75  Ib.  per  square  inch.  (For  a  description  of  the  plant 
required  for  the  application  of  the  pressure  treatment  'to  poles, 
the  reader  is  referred  to  Forest  Service  Bulletin  No.  84.)  If  the 
poles  be  wet  or  green  they  are  steamed  for  from  five  to  eight 
hours,  with  the  steam  maintained  at  a  pressure  of  from  12  Ib. 
to  17  Ib.,  and  if  partially  seasoned,  for  from  three  to  five  hours 
at  from  15  Ib.  to  20  Ib.  pressure;  seasoned  poles  are  not  steamed 
but  are  subjected  to  heat  at  150°  F.,  maintained  for  from  one  to 
two  hours  by  means  of  steam  coils.  Then,  if  the  poles  being 
treated  are  green,  wet,  or  partially  seasoned,  a  vacuum  of  at  least 
24  in.  at  sea  level,  and  proportionate  for  higher  elevations,  is 
maintained  for  from  one  to  two  hours,  with  the  temperature  in 
the  cylinder  kept  at  a  little  above  the  boiling-point  during  the 
time  the  vacuum  is  on;  if  the  poles  be  seasoned,  the  exhaustion 
part  of  the  process  is  omitted.  The  final  step  in  the  treatment 
consists  in  filling  the  cylinder  as  rapidly  as  possible  with  creosote 
at  a  temperature  of  not  less  than  140°  and  not  more  than  175°  F. 
and  applying  pressure  sufficient  to  secure  the  absorption  desired. 
The  absorption  is  determined  by  measurement  of  the  oil,  which 
is  withdrawn  from  the  measuring  tank,  with  due  temperature 
corrections. 

The  only  objection  to  this  process  is  the  liability  of  the  creo- 
sote to  exude  and  appear  upon  the  surface  of  the  pole,  making  nec- 
essary the  protection  of  the  pole  butt  from  contact  by  pass- 
ersby  where  the  poles  are  located  along  the  streets  in  a  city;  in 
transmission  line  work,  of  course,  this  objection  will  not  often 
obtain,  but  nevertheless  it  is  a  question  whether  or  not  the  appli- 
cation of  a  vacuum  for  a  short  period  following  the  pressure  stage 
of  the  treatment  would  not  extract  the  surplus  oil  in  the  sap-wood 
without  diminishing  the  value  of  the  treatment  or  withdrawing 
any  oil  at  all  from  the  heart-wood,  compromising  slightly  between 
the  full  cell  and  the  partial  cell  processes. 

The  cost  of  treating  the  entire  length  of  the  pole  with  creosote, 
either  by  the  open  tank  or  the  pressure  methods,  as  estimated  by 
the  Forest  Service  is  $1.10  for  a  5-in.  top,  25-ft.  loblolly-pine  pole 


WOODEN  POLE  CONSTRUCTION  69 

and  $2.45  for  a  6-in.  top,  35-ft.  pole  of  the  same  species;  the  cost 
is  based  upon  an  absorption  of  10  Ib.  per  cubic  foot. 

As  given  in  the  Electrical  World  for  June  1,  1911,  the  cost 
f.o.b.  Birmingham,  Ala.,  for  southern  pine  poles  with  a  12-lb. 
creosote  treatment  of  the  entire  pole  is  as  follows: 

30  ft.    8-in.  tops $  6.95 

30  ft.  10-in.  tops 8 . 30 

30  ft.  13-in.  tops 11.35 

35  ft.    8-in.  tops 7 . 85 

35  ft.  10-in.  tops 9 . 90 

The  cost  of  these  poles  is  about  double  that  of  the  untreated 
poles,  and  this  ratio  appears  to  hold  good  generally  over  the 
country. 

In  the  Electrical  World  for  Sept.  30,  1911,  a  description  is  given 
of  a  machine  that  has  been  developed  for  the  application  of 
creosote  under  pressure  to  a  narrow  belt  at  the  ground  line,  in 
this  case  for  a  space  of  3  ft.  The  machine  is  portable,  about  19 
ft.  long  and  6  ft.  wide,  and  is  easily  handled  by  one  team;  it  is 
self-contained  and  includes  a  steam  boiler,  an  air  compressor  and 
storage  tank,  a  closed  oil  tank  containing  steam  coils  for  heating 
the  oil,  an  air-tight  canvas  band  which  encases  the  pole  at  the 
zone  to  be  treated,  and  the  necessary  gearing  and  mechanism  to 
pass  this  band  about  the  pole  and  tighten  it  to  resist  pressure. 
The  pole  is  rolled  onto  the  machine  and  the  canvas  band  brought 
around  it,  made  fast  and  clamped  at  the  ends;  then  the  hot  oil, 
by  means  of  air  pressure  in  the  oil  tank,  is  forced  under  this  band, 
and  the  pressure  maintained  for  from  ten  to  fifteen  minutes 
ordinarily;  suitable  arrangements  are  provided  for  catching 
drips  and  leakage  and  returning  them  to  the  oil  tank.  A  35-ft. 
northern  cedar  pole  with  a  ten-minute  treatment  under  5  Ib. 
pressure,  showed  a  penetration  of  3/16-in.  with  an  absorption  of 
about  1  gallon  or  approximately  8  1/2  Ib.  in  the  3-ft.  belt.  The 
capacity  of  the  machine  is  said  to  be  fifty  poles  a  day,  and  it  will 
handle  any  diameter  from  7  in.  to  24  in. 

While  no  attempt  has  been  made  to  describe  the  various 
methods  of  preservation  by  the  use  of  metallic  salts,  such  as  zinc 
chloride,  mercuric  chloride,  copper  sulphate,  etc.,  the  applications 
of  which,  however,  do  not  differ  greatly  from  the  tank  methods 
described  for  creosote,  it  will  be  interesting  to  note  the  value  of 
the  various  methods  in  fulfilling  their  purposes.  Below  is  given 
the  average  life  of  poles  as  determined  from  statistics  of  the 


70  TRANSMISSION  LINE  CONSTRUCTION 

Telegraph  Department  of  the  German  Government  covering  a 
period  of  more  than  fifty  years.  In  comparing  these  figures  due 
consideration  must  be  given  to  the  fact  that  mineral  salt  treat- 
ments are  somewhat  cheaper  than  creosote;  also  the  cost  of 
making  replacements  here  and  there  along  the  length  of  a  line 
enters  into  any  comparisons  of  the  relative  efficiencies  of  pre- 
servatives with  especial  force  when  the  poles  are  to  be  used  for 
transmission  line  work. 

The  average  life  of  poles  treated  as  below  is  as  follows: 

Copper  sulphate 11.7  years. 

Zinc  chloride 11.9  years. 

Mercuric  chloride 13 . 7  years. 

Creosote  (coal  tar) 20 . 6  years. 

Untreated 7.7  years. 

The  same  statistics  as  noted  in  the  report  of  the  National  Electric 
Light  Association  committee  on  the  subject  show  that  almost 
90  per  cent,  of  the  poles  observed  were  treated  with  copper  sul- 
phate, 5.5  per  cent,  with  mercuric  chloride  and  only  about  3  per 
cent,  with  creosote. 

While  the  matter  of  applying  creosote  treatment  to  timber 
appears  on  the  surface  to  be  a  simple  proposition,  much  trouble 
has  been  experienced  in  securing  the  results  called  for;  there  is 
so  much  opportunity  for  poor  work,  through  inferior  creosote, 
misjudgment  in  the  application  and  deliberate  attempts  to 
defraud,  that  specifications  should  be  closely  drawn  for  every 
detail  and  provision  made  for  competent  inspection  at  the  plant. 
Much  variety  is  apparent  in  the  specifications  for  the  creosote 
itself,  and  many  cases  have  been  recorded,  especially  in  the 
treatment  of  piling,  where  creosote  with  a  high  percentage  of 
the  lighter  oils  has  volatilized  in  a  very  short  time.  From  the 
investigation  of  the  Forest  Service  it  appears  that  the  heavy  oils, 
containing  a  high  proportion  of  anthracene  oil,  remain  in  the 
timber  indefinitely,  the  naphthalene  oils  for  an  extended  period, 
but  the  tar  acids,  which  have  been  credited  as  of  great  value, 
appear  to  work  out  of  the  timber  in  a  short  time;  therefore  it 
seems  that  the  most  effective  creosote  (dead  oil  of  coal  tar)  is 
that  which  contains  a  fairly  large  proportion  of  high-boiling 
constituents.  The  specifications  for  creosote  as  called  for  by 
one  of  the  large' telephone  companies,  are  given  in  the  appendix. 

In  general  in  the  United  States,  it  is  only  within  the  past  few 
years  that  much  attention  has  been  given  to  the  possibilities  of 


WOODEN  POLE  CONSTRUCTION  71 

timber  preservation  as  applied  to  poles;  the  abundant  supply 
and  the  lower  demand  of  a  few  years  ago  resulted  in  prices  that, 
with  the  slight  attention  given  to  the  subject,  did  not  appear  to 
display  any  opportunities  for  saving.  The  reversal  of  conditions 
brought  the  matter  up  sharply  and,  following  the  lead  of  the 
larger  telegraph  and  telephone  companies,  power  companies  are 
now  rapidly  adopting  some  one  of  the  various  preservative 
methods. 

Whether  or  not  the  use  of  a  preservative  will  be  warranted 
under  any  particular  set  of  conditions,  will  have  to  be  made  a 
subject  of  study  under  the  particular  conditions  obtaining;  it  is 
open  to  mathematical  determination  from  a  comparison  of  the 
annual  costs  of  the  different  poles  as  outlined  below.  The  pole 
timbers  available  in  the  particular  locality,  both  untreated  and 
with  preservatives  applied,  are  listed  with  their  respective  costs 
per  pole  in  place  in  the  line  and  with  their  estimated  serviceable 
life  in  years;  then,  using  this  initial  cost  and  the  life  in  each  case, 
and  allowing  the  usual  local  interest  chrge  in  the  calculation, 
the  annual  cost  of  each  of  the  different  kinds  of  poles  can  be 
obtained,  giving  a  direct  comparison  between  them.  It  is  very 
seldom  that  the  application  of  a  preservative  will  not  show  a 
saving. 

For  transmission  line  work  as  ordinarily  constructed  (as  tall 
poles  are  not  generally  required  as  they  are  for  city  distribution 
lines),  the  standard  height  of  pole  adopted  is  usually  35  ft.  or 
40  ft.  for  spans  up  to  say,  150  ft.;  the  top  diameter  for  straight- 
line  work  is  either  7  in.  or  8  in.  Horizontal  grading  of  the  line 
will  call  for  some  poles  shorter  and  some  longer  than  the  standard, 
the  minimum  height  of  pole  being  naturally  determined  by  the 
vertical  clearance  required  under  the  conditions  and  the  maxi- 
mum by  economy  and  safety,  and  for  average  35-ft.  and  40-ft. 
lines  it  is  good  policy  to  work  with  60-ft.  or  65-ft.  poles  as  the 
maximum  allowed,  and  at  that,  employing  them  only  where  a 
change  in  spacing,  use  of  long  span  with  heavier  construction, 
etc.,  cannot  be  substituted. 

In  buying  poles  many  companies  consider  the  top  diameter 
only,  specifying  for  instance,  "so  many  7-in.  top,  35-ft.  cedar 
poles  in  accordance  with  Northwestern  Cedarmen's  Association 
Specifications,"  no  mention  being  made  oi'the  butt;  this  method 
of  purchasing  is  akin  to  calling  for  a  9-in.  I-beam,  16  ft.  long, 
without  specifying  its  weight  per  foot.  This  "scientific" 


72 


TRANSMISSION  LINE  CONSTRUCTION 


method  of  buying  poles  is  not  confined  altogether  to  small  com- 
panies either,  and  one  often  wonders  if  the  computation  of  the 
strain  on  a  pole  is  not  so  simple  that  engineers  oftentimes  prefer 
to  guess  at  it,  rather  than  stop  to  figure  out  what  their  special 
conditions  call  for.  In  general,  for  one  or  two  circuits  of  from 
No.  6  to  No.  1  B.  &  S.  conductors,  poles  fulfilling  the  specifica- 
tions given  in  Table  III  will  be  used;  for  lines  carrying  conductors 
of  from  No.  1  to  No.  0000  in  size,  heavier  ones  as  given  in  Table  IV 
will  be  called  for;  it  will  be  noted,  however,  that  these  figures 
are  for  average  conditions  and  for  average  spans,  about  125  ft. 
to  150  ft.  for  the  lighter  lines  and  from  110  ft.to  125  ft.  for  the 
heavier  lines,  and  that  local  weather  conditions  such  as  heavy 
sleet  and  high  winds,  etc.,  must  always  be  taken  into  con- 
sideration and  allowed  for. 

TABLE  III 


Northern  cedar 

White  chestnut 

Juniper 

Length, 

ft. 

Top, 
in. 

6   ft.   up 
from 
butt,  in. 

Length, 
ft. 

Top, 
in. 

6  ft.   up 
from 
butt,  in. 

Length, 
ft. 

Top, 
in. 

6  ft.  up 
from 
butt,  in. 

30 

22 

36 

30 

22 

32 

30 

22 

33 

35 

22 

38 

35 

22 

36 

35 

22 

36 

40 

22 

43 

40 

22 

40 

40 

22      [         40 

45 

22 

47 

45 

22 

43 

45 

22 

45 

50 

22 

50 

50 

22 

47 

50 

22 

47 

55 

22 

53 

55 

22 

50 

55 

22 

50 

60 

22 

56 

60 

22 

53 

60 

22 

56 

Top  and  butt  measurements  for  poles  are  for  circumferences. 

TABLE  IV 


Northern  cedar 

White  chestnut 

Juniper 

Length, 

ft. 

Top, 
in. 

6  ft.  up 
from 
butt,  in. 

Length, 
ft. 

Top, 
in. 

6  ft.  up 
from 
butt,  in. 

Length, 
ft. 

Top, 
in. 

6  ft.  up 
from 
butt,  in. 

i 

30 

25 

41 

30 

25 

36 

30 

25 

36 

35 

25 

44 

35 

25 

40 

35 

25 

40 

40 

25 

48 

40 

25 

43 

40 

25 

44 

45 

25 

51 

45 

25 

47 

45 

25 

48 

50 

25 

54 

50 

25 

50 

50 

25 

51 

55 

25 

57 

55 

25 

53 

55 

25 

53 

60 

25 

60 

60 

25 

56 

60 

25 

57 

WOODEN  POLE  CONSTRUCTION  73 

The  cost  of  wooden  poles  has  varied  considerably  in  the  last 
few  years,  but  the  figures  below  give  current  prices  for  1911-12, 
on  northern  and  western  cedar. 

NORTHERN  CEDAR  F.O.B.  MINNEAPOLIS,  MINN. 

30-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  36  in $4.60 

35-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  38  in 6.70 

35-ft.  pole,  circumference  top,  24-in.,  butt,  6  ft.  up,  40  in 6.95 

40-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  43  in 7.50 

45-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  47  in 10.25 

50-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  50  in 11 .90 

55-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  53  in 15. 10 

60-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  56  in 22.50 

65-ft.  pole,  circumference  top,  22-in.,  butt,  6  ft.  up,  59  in 29.00 

WESTERN  CEDAR  POLES  F.O.B.  SPOKANE,  WASH. 

Note. — No  butt  measurements  given;  taper  is  approximately  1  in.  to 
every  8  ft.  of  the  length. 

30-ft.  pole,  6-in.  top $  1 . 75 

30-ft.  pole,  7-in.  top 2 . 50 

30-ft.  pole,  8-in.  top 2 . 85 

35-ft.  pole,  6-in.  top 2 . 75 

35-ft.  pole,  7-in.  top 3 . 25 

35-ft.  pole,  8-in.  top 3 . 75 

40-ft.  pole,  7-in.  top 3 . 75 

40-ft.  pole,  8-in.  top 4.25 

45-ft.  pole,  7-in.  top 4.25 

45-ft.  pole,  8-in.  top ... 5 . 00 

50-ft.  pole,  7-in.  top . 5 . 00 

50-ft.  pole,  8-in.  top 5.50 

55-ft.  pole,  7-in.  top ...  5.50 

55-ft.  pole,  8-in.  top 6 . 00 

60-ft,  pole,  8-in.  top . .  7 .00 

65-ft.  pole,  8-in.  top 8 . 50 

70-ft.  pole,  8-in.  top 10 .00 

In  western  cedars,  the  6-in.  tops  must  measure  18£  in.  in  circumference,  the 
7-in.  tops,  22  in.,  and  the  8-in.  tops,  25  in. 

The  loading  of  poles  for  shipment  varies  with  different  rail- 
road companies;  for  instance,  one  road  sets  24,000  Ib.  as  the 
minimum  load  for  poles  up  to  and  including  30-ft.  lengths 
while  for  poles  35  ft.  and  more  in  length  the  minimum  is  30,000 
Ib.;  another  road  sets  the  minimum  car-load  at  30,000  Ib.  for 
poles  up  to  34  ft.  in  length  and  for  all  poles  over  that,  34,000  Ib. 
Below  in  Table  V  are  given  shipping  data  for  northern  cedar 
poles  as  furnished  by  various  pole  companies. 


74 


TRANSMISSION  LINE  CONSTRUCTION 


TABLE  V.— NORTHERN  CEDAR,  WEIGHTS  AND  CAR 
LOADING 


Length,  ft. 

Circumfer- 
ence. 
Top,  in. 

Circumfer- 
ence. 
6  ft.  up  from 
butt,  in. 

Weight  of 
each,  Ib. 

Number  per  load 

30 

22 

36 

450 

55  to  95  single  car. 

30 

24 

41 

550 

45  to  80  single  car. 

35 

22 

38 

600 

50  to  70  single  car. 

35 

24 

44 

730 

40  to  60  single  car. 

40 

22 

43 

800 

40  to  55  single  car. 

40 

24 

48 

975 

30  to  45  single  car. 

45 

22 

47 

1,000 

60  to  70  double  car. 

45 

24 

51 

1,150 

52  to  58  double  car. 

50 

22 

50 

1,250 

48  to  55  double  car. 

50 

24 

54 

1,350 

44  to  48  double  car. 

55 

22 

53 

1,550 

39  to  42  double  car. 

55 

24 

57 

1,750 

34  to  37  double  car. 

60 

22 

56 

2,000 

30  to  33  double  car. 

65 

22 

59 

2,700 

23  to  25  double  car. 

In  this  Table  V  of  shipping  weights  and  loading  for  northern 
cedars,  it  will  be  noted  that  all  lengths  up  to  and  including 
65  ft.  are  listed;  as  a  matter  of  fact,  60-ft.  and  65-ft.  poles  are  prac- 
tically unobtainable  and  8-in.  tops  in  poles  over  40  ft.  in  length 
are  very  hard  to  get;  western  cedar  is  still  obtainable  in  any 
top  and  length  commercially  used,  at  prices  in  the  Middle  West 
that  compete  with  northern  cedar,  but  the  length  of  time 
required  for  delivery  is  a  great  drawback  and  bars  them  from 
consideration  in  many  cases. 

Western  cedar  runs  lighter  than  northern  cedar  for  the  same  size 
top  and  length  on  account  of  its  slimmer  taper,  averaging  about  80 
per  cent,  to  85  per  cent,  the  weight  of  the  northern;  chestnut  is 
heavy  compared  with  cedar,  running  from  60  per  cent,  to  100  per 
cent,  greater  in  weight  for  the  same  average  sizes;  cypress  is  also 
much  heavier  than  cedar;  juniper  or  southern  white  cedar  is 
slightly  heavier  than  the  northern  cedar;  pine  runs  from  40  per 
cent,  to  50  per  cent,  heavier  than  northern  cedar. 

The  unloading  of  car-loads  of  poles  is  a  simple  matter;  many 
companies  continue  the  old  practice  of  cutting  off  the  stakes 
and  letting  them  roll  off,  often  at  the  expense  of  accidents  and 


WOODEN  POLE  CONSTRUCTION  75 

of  cracked  poles;  the  safer  and  better  method  is  to  use  ropes 
fastened  underneath  the  car  on  the  unloading  side,  passed  over 
the  top  of  the  poles  and  snubbed  on  the  far  side;  then  the  stakes 
and  wire  may  be  cut  and  the  poles  snubbed  down  on  to  the  skids 
in  safety  and  under  control.  As  noted  earlier  in  the  chapter, 
poles  should  be  skidded  in  single  layers  if  possible,  laid  out 
either  on  other  poles  blocked  up  off  the  ground,  or  on  old  sound 
timbers,  and  all  decaying  rubbish  and  all  weeds  that  can  grow 
up  into  contact  with  the  poles  or  so  as  to  impede  the  circulation 
of  air  underneath  them  should  be  removed.  Where  it  is  not 
practicable  to  store  all  the  poles  in  single  layers,  the  following 
courses  should  be  laid  out  with  poles  in  between  them  in  the 
same  manner  as  the  skids  at  the  bottom  are  arranged. 

The  cost  per  pole  for  unloading  and  skidding,  varies  naturally 
with  the  size  and  kind  of  pole  and  with  the  track  conditions; 
the  figures  given  below  are  based  upon  the  handling  of  the 
average  run  of  northern  cedar  poles  of  7-in.  top,  with  foreman 
at  $3.50  to  $4,  linemen  at  $2.75  and  groundmen  at  $1.75  to  $2 
a  day. 

Unloading  30-ft.  poles  costs  from  5  to  8  cents  each. 
Unloading  35-ft.  poles  costs  from  8  to  12  cents  each. 
Unloading  40-ft.  poles  costs  from  12  to  15  cents  each. 
Unloading  45-ft.  poles  costs  from  15  to  18  cents  each. 
Unloading  50-ft.  poles  costs  from  20  to  25  cents  each. 
Unloading  55-ft.  poles  costs  from  25  to  30  cents  each. 
Unloading  60-ft.  poles  costs  from  30  to  35  cents  each. 

These  figures  are  based  upon  average  conditions  met  with 
in  the  construction  of  high-tension  transmission  lines  in  the 
Middle  West;  the  laying  of  skid  poles  is  included  and  poles  are 
unloaded  in  single  layers;  where  the  unloading  is  done  in 
restricted  quarters,  the  cost  will  be  higher.  For  poles  other 
than  cedar,  the  cost  is  closely  proportional  to  the  respective 
car  loadings. 

For  the  handling  of  poles  for  distribution,  a  little  attention  to 
systematizing  the  arrangement  of  the  poles  in  the  yards  will  not 
only  cut  down  the  cost  of  distribution  but  will  allow  greater  prog- 
ress in  the  work.  In  the  first  place  the  poles  should  be  laid  out 
so  that  teams  will  have  easy  access  to  them;  then  all  poles  of  the 
same  nominal  length  and  diameter  of  top  should  be  skidded  to- 
gether in  separate  piles;  ordinarily  there  will  probably  be  only 
two  or  three  sizes  in  which  any  number  of  poles  will  have  been 


76  TRANSMISSION  LINE  CONSTRUCTION 

ordered  and  the  few  extra  length  poles  can  be  placed  together. 
Where  close  attention  is  to  be  given  to  the  grading  of  the  line  it 
will  be  well  to  go  through  the  piles  and  measure  up  poles  that 
run  a  little  above  or  below  the  standard  length,  chalking  the 
actual  measurement  on  the  butt  of  the  pole,  as  it  is  apparent  that 
these  odd  lengths  can  be  used  to  very  good  advantage  in  grading. 
It  is  a  good  plan  at  least  to  mark  all  extra  length  poles,  with  the 
top  diameter  and  length  measurements,  so  that  in  loading  up 
teams  no  time  need  be  taken  to  check  up  dimensions  and  also 
that  the  chances  of  incorrect  lengths  being  sent  out,  may  be 
minimized. 

In  loading  poles  upon  wagons  for  hauling  out,  a  gin  pole  set 
facing  the  skidway  a  sufficient  distance  away  so  that  the  wagons 
can  be  driven  in  between  it  and  the  poles,  is  a  great  time-saver, 
and  with  teams  at  from  $3.50  to  $5  a  day  this  is  an  important 
item.  The  gin  pole  is  rigged  with  a  pair  of  double  blocks,  reeved 
with  a  rope  long  enough  to  permit  a  long  extension  of  the  blocks 
and  yet  leave  enough  fall  line  to  pass  down  through  a  snatch 
block  hooked  in  a  sling  at  the  butt  of  the  gin  pole,  so  that  a  team 
can  be  used  for  the  pulling;  where  the  amount  of  work  is  con- 
siderable, a  crab  may  be  rigged  to  take  the  place  of  the  team. 
Where  the  company  is  in  possession  of  a  gin  wagon  used  for  set- 
ting poles,  this  can  be  utilized  very  nicely  for  the  loading  and  is 
somewhat  better  than  a  gin  pole  in  that  it  can  be  moved  about 
more  readily. 

In  distributing  poles  or  for  that  matter  any  line  material, 
difficulty  is  often  experienced  in  getting  teamsters  to  take  out 
full  loads,  and  a  competent  and  "  non-bluff  able"  loading  boss 
can  materially  influence  the  distribution  cost.  The  loading  boss 
or  yard  foreman  will  have  as  his  guide  in  supervising  the  pole 
distribution,  a  copy  of  the  data  book  described  in  Chapter  II 
and  illustrated  in  Fig.  2,  giving  pole  heights,  etc.,  corresponding 
to  the  numbered  survey  stakes,  from  which  in  connection  with 
the  map  of  the  line  and  the  routing  instructions,  he  will  be  able  to 
direct  the  teamsters  as  to  the  best  roads,  etc.,  to  use.  Teams 
should  be  sent  out  in  threes  or  fours  so  that  they  can  help  each 
other  out  if  bad  spots  in  the  road  or  steep  hills  be  encountered. 
Poles  as  loaded  at  the  yard  will  be  numbered  in  accordance  with 
their  location,  so  that  the  only  discretion  that  need  be  exercised 
on  the  part  of  teamsters  is  to  unload  their  poles  at  the  stakes 
bearing  the  same  numbers;  the  care  and  accuracy  shown  in 


WOODEN  POLE  CONSTRUCTION  77 

carrying  this  out  will  be  checked  by  the  general  foreman  in  the 
field.  It  is  a  good  policy  to  keep  a  record  of  the  pole  numbers 
hauled  out  by  the  various  teamsters  as  oftentimes  some  of  the 
company's  poles  will  be  found  unloaded  at  some  little  distance 
from  their  proper  location,  especially  if  there  be  some  hard  work 
involved  in  the  getting  of  them  to  their  proper  place  and,  in  the 
absence  of  record,  no  one  will  be  -found  to  have  hauled  those 
particular  poles. 

The  cost  of  handling  and  transporting  a  pole  from  the 
yard  to  its  location  out  on  the  line  varies  in  any  one  locality  for 
a  certain  size  pole,  with  the  time  of  the  year  in  which  the  work 
is  carried  on,  upon  the  weather  conditions  prevailing  and,  of 
course,  upon  the  average  length  of  haul;  in  different  localities  it 
will,  in  addition  to  the  above,  vary  with  the  character  of  the 
country  traversed  and  the  prevailing  labor  conditions. 

For  9-in.  top,  40-ft.  and  50-ft.  cypress  hauled  out  in  winter  time 
on  wagons,  on  account  of  poor  sledding,  with  teams  at  $3.50  a 
day  and  an  average  haul  of  4  to  4  1/2  miles,  the  cost  was  from 
40  cents  to  50  cents  per  pole;  these  poles  were  wet  and  heavy  and 
consequently  the  number  of  poles  to  a  load  was  small,  though  the 
roads  were  generally  good  and  fairly  level;  also  their  weight  com- 
bined with  large  flaring  butts  made  them  awkward  to  unload  at 
their  destination.  The  cost  given  does  not  include  any  charge 
for  general  superintendence  or  general  expense,  but  does  include 
all  yard  labor. 

For  a  line  in  Minnesota  using  7-in.  top,  35-ft.  northern  cedar 
poles,  the  cost  for  distribution  of  the  poles  was  about  25  cents 
each;  the  average  length  of  haul  was  about  3  miles  and  the  work 
was  carried  on  in  the  early  fall  over  fair  country  roads  through 
rolling  country;  teams  cost  $4  a  day;  this  line  was  built  along  the 
highway  for  most  of  the  way  and  the  poles  were  dry  and  easily 
handled.  The  figure  includes  all  yard  and  team  labor  but  no 
charge  for  general  superintendence  or  general  expense. 

In  the  West  where  lines  are  built  through  rough  mountainous 
country  and  through  unsettled  regions  in  many  cases,  the  cost 
of  distributing  the  line  material  is  very  high  and  the  cost  per 
pole,  in  one  instance  under  such  conditions,  was  estimated  by  the 
company  in  the  absence  of  segregated  costs,  at  90  cents  for  7-in. 
top,  35-ft.  western  cedars;  the  average  haul  was  about  8  miles 
to  9  miles. 

Another   western   operating   company   which   recently   built 


78  TRANSMISSION  LINE  CONSTRUCTION 

about  85  miles  of  pole  line  using  8-in.  top,  45-ft.  western  cedars 
in  300-ft.  spans,  gives  the  average  cost  per  pole  for  hauling  at 
$1.50;  this  appears  to  include  the  distribution  of  cross-arms  and 
hardware  and  allowing  the  high  figure  of  20  cents  per  pole  for 
this,  the  distribution  cost  per  pole  for  the  poles  alone  was  about 
$1.30  each. 

The  framing  of  poles  for  transmission  line  work  is  in  most  cases 
done  in  the  field,  though  sometimes  the  work  is  carried  on  in  the 
pole  yard.  The  framing  of  9-in.  top,  40-ft.  and  50-ft.  cypress 
poles,  including  roofing,  cutting  two  gains  for  5-in.  X  7-in.  arms 
boring  two  3/4-in.  holes,  averaged  about  45  cents,  three  men  aver- 
aging about  twenty-two  poles  a  day,  working  in  the  yards. 
On  a  job  using  7-in.  top,  35-ft.  northern  cedars,  three  men,  one 
at  $2.50  and  two  at  $2  tor  a  ten-hour  day,  framed  and  attached 
a  patent  steel  cross-arm  for  single-circuit  60,000-volt  construc- 
tion to  an  average  of  about  thirty  poles  a  day,  or  at  a  cost  of 
about  22  cents  each,  not  including  proportion  of  foreman's  time, 
general  superintendence  or  expense;  this  construction  required 
no  sawing  except  at  the  roof,  the  rest  being  only  f acing-off  with 
a  hand- ax.  The  cost  of  framing  for  a  line  of  8-in.  top,  45-ft.  and 
50-ft.  western  cedars,  with  two  gains  for  4-in  x  5-in.  arms  and  one 
for  a  telephone  arm  below  is  given  at  $1  per  pole;  this  work  was 
done  under  unfavorable  conditions  with  high-priced  labor  and 
includes  the  attachment  of  the  arms.  Where  the  framing  is  done 
in  the  field  as  is  usually  the  case,  a  saving  over  the  system  of 
carrying  this  on  in  the  pole  yard  is  effected,  in  that  the  work 
of  cutting  gains,  boring,  etc.,  is  merged  with  that  of  attaching 
the  arms  and  braces;  also  it  is  more  convenient  where  the  grading 
of  the  line  may  call  for  the  sawing  off  of  poles.  In  general  for  7-in. 
and  8-in.  top  cedar  poles  35ft.  to  40-ft.  long,  the  cost  of  roofing 
will  run  about  10  cents  and  the  cutting  of  gains  about  10  cents 
to  15  cents  per  gain,  based  upon  average  arms  such  as  4  in.  X5 
in.  and  larger,  as  will  be  used  in  high-tension  work.  The  cost  of 
fitting  cross-arms  in  the  foregoing  cases  will  run  from  8  cents  to  15 
cents  when  the  work  is  done  on  the  ground,  and  from  15  cents 
to  25  cents  when  done  in  the  air  after  setting;  the  great  variation 
is  due  to  the  fact  that  the  cost  per  arm  where  only  one  arm  per 
pole  is  carried  is  higher  than  where  several  arms  are  to  be  fitted 
with  one  climb  or  one  move;  average  length  of  arm  assumed  at 
about  6  ft. 

The  cost  of  digging  holes  for  setting  poles  is  even  more  variable 


WOODEN  POLE  CONSTRUCTION  79 

than  that  of  most  of  the  other  steps  in  the  work,  depending  upon 
the  character  of  the  soil,  the  time  of  the  year,  the  local  weather 
conditions  and  naturally  upon  the  size  and  length  of  the  poles. 
The  depths  to  which  poles  should  be  set  in  average  soil  are  given 
in  Table  VI,  which  represents  the  general  practice  in  America; 
where  the  setting  is  in  solid  rock,  the  depth  of  holes  is  usually 
2  ft.  less  than  the  tabular  figures  and  for  corner  poles  in  average 
soil,  1  ft.  more;  for  soft  ground  the  depth  is  increased  about  1  ft. 
In  digging  on  hillsides  the  measurement  is  taken  from  the  low 
side  of  the  hole  and  in  the  case  of  steep  slopes,  the  depth  of  set 
is  increased  as  may  be  deemed  necessary. 

TABLE  VI.— DEPTH  OF  SETTING  FOR  WOODEN  POLES  IN 
AVERAGE  GROUND 

30-ft.  pole set  5    ft. 

35-ft.  pole set  5£  ft. 

40-ft.  pole set  6    ft. 

45-ft.  pole set  6£  ft. 

50-ft.  pole set  7    ft. 

55-ft.  pole set  1\  ft. 

60-ft.  pole set  8    ft. 

65-ft.  pole set  8£ft. 

70-ft.  pole set  9    ft. 

Holes  should  be  dug  so  as  to  leave  about  a  3-in.  tamping  space 
all  around  the  pole,  and  should  be  cut  full  to  the  bottom  so  as 
to  allow  of  easy  lining  in  and  tamping. 

Holes  for  the  greater  part  of  a  line  of  9-in.  top,  40-ft.  cypress 
poles  with  a  standard  setting  of  6  ft.  were  dug  at  the  average 
rate  of  about  eight  holes  per  nine-hour  day  per  man  with  men  at 
$1.75  per  diem;  with  board  allowance  and  part  time  of  foreman 
and  team  proportionately  charged,  the  cost  per  pole  was  about 
35  cents.  The  soil  was  sandy  and  damp  enough  to  hold  up  well 
so  that  the  digging  was  easy,  though  the  flaring  butts  of  the  poles 
required  holes  of  large  diameter;  in  cases  where  water  was  en- 
countered as  in  bottom  land,  the  cost  per  hole  varied  from  75 
cents  to  $2  each.  The  latter  figure  is  for  holes  where  much 
tough  blue  clay  and  quicksand  were  encountered  and  where, 
with  no  sand-pump  available,  the  sand  and  water  had  to  be 
scooped  out  with  pails  and  sand  barrels.  These  figures  include 
all  labor  and  field  expense  but  not  general  superintendence, 
locating,  or  general  expense. 


80  TRANSMISSION  LINE  CONSTRUCTION 

In  digging  for  a  line  of  7-in.  top,  35-ft.  northern  cedars  in 
medium  clay  ground  built  in  early  fall,  one  man  working  ten 
hours  would  dig  from  three  to  five  holes  5  1/2  ft.  in  depth;  diggers 
were  paid  $2  a  day  and  the  average  cost  per  hole,  including 
foreman  and  team  time,  was  about  62  cents. 

In  another  case  where  the  work  was  carried  on  under  high- 
priced  labor  conditions  in  isolated  regions,  the  cost  of  digging- 
holes  for  a  line  of  8-in.  top,  45-ft.  and  50-ft.  poles  is  given  at  $2.60; 
much  rock  was  encountered  and  the  poles  are  set  in  about  300-ft. 
spans. 

In  Contracting  Engineering  for  Feb.  5,  1908,  the  cost  of  digging 
for  a  line  of  32-ft.  poles  is  given  as  about  $1  per  pole;  this  involved 
only  a  short  piece  of  line,  with  few  men,  the  charge  being  foreman 
23  cents  and  groundmen  75  cents  or  a  total  of  $0.98  per  hole 
actual;  the  soil  was  a  red  sandy  clay  and  judging  from  the 
figures  one  man  must  have  dug  only  an  average  of  two  holes  per 
diem,  as  the  wage  scale  is  $1.50  a  day  with  no  reference  to  board 
allowance.  In  the  same  journal  for  March  4,  1908,  an  interesting 
summary  of  the  digging  cost  for  about  600  trolley  poles  is  given; 
the  work  was  carried  on  from  February  to  July  with  diggers  at 
$1.50  and  a  foreman  at  $3  per  ten-hour  day,  and  for  320  holes 
averaging  about  63/4  ft.  deep  and  3  1/2  ft.  in  diameter,  the 
cost  was  $1.33  each;  sixty-four  holes  6  ft.  deep  and  about  2  ft. 
in  diameter  cost  79  cents  each;  the  first  lot  of  holes  were  dug  in 
cinder  and  slag  fill  where  much  trouble  was  experienced  from 
caving-in,  while  the  last  sixty-four  mentioned  were  dug  in 
original  ground. 

In  Contr acting-Engineering  for  May  27,  1908,  figures  are  given 
for  a  small  city  construction  job  where  the  cost  of  digging  51/2- 
ft.  holes  is  noted  as  averaging  $0.47|  each. 

Digging  in  wet  ground  where  muck  and  quicksand  are 
encountered,  and  blasting  pole-holes  in  rock,  are  expensive 
operations.  In  the  first  case  the  holes  will  have  to  be  sheathed 
in  some  way,  either  by  the  use  of  ordinary  stave  packing  barrels, 
horizontal  plank  cribbing,  vertical  plank  shoring,  or  steel  plate 
sand  barrels.  The  first  three  methods  are  the  same  as  may  be 
used  in  any  excavation  work.  The  sand  barrel  is  a  cylinder  of 
about  1/4-in.  boiler  plate,  made  of  the  length  and  diameter 
called  for  by  the  maximum  size  of  pole  to  be  set  in  the  particular 
case,  and  constructed  in  halves  split  vertically  and  arranged  with 
bands  by  means  of  which  the  two  halves  are  pinned  together  in 


WOODEN  POLE  CONSTRUCTION  81 

the  manner  of  a  hinge,  the  bands  also  acting  to  stiffen  the 
cylinder;  these  are  driven  down  as  the  excavation  proceeds  and 
where  much  wet  digging,  especially  with  quicksand,  is  encoun- 
tered, they  will  pay  for  themselves.  After  raising  the  pole,  the 
pins  of  the  barrel  are  drawn,  and  by  means  of  a  pair  of  blocks 
rigged  from  the  pole  and  hooked  into  an  eye  on  the  barrel,  each 
half  is  pulled  out  separately.  For  isolated  wet  holes,  a  couple  of 
ordinary  barrels  will  answer,  and  2-in.  X6-in.  or  2-in.  x8-in. 
shoring  is  also  very  satisfactory,  especially  where  the  poles  are 
set  with  a  gin  wagon. 

Rock  holes  are  the  most  expensive  of  all  excavation  for  pole 
setting,  the  average  for35-ft.  and  40-ft.  poles  running  from  $2. 50 
to  $3.50  per  hole;  where  very  hard  rock  is  encountered  in  isolated 
stretches,  the  cost  may  exceed  the  maximum  figure;  in  one  case 
where  holes  were  blasted  in  hard  trap  rock,  the  cost  for  a  40-ft. 
line  ran  from  $4  to  $4.50  each;  two  men  averaged  one-half  day 
per  hole  and  the  cost  of  drill-sharpening  was  about  $1  per 
hole. 

In  ordinary  digging  work  each  member  of  the  crew  should  be 
equipped  with  a  D-handle  No.  2  round-point  shovel,  a  long- 
handled  (about  8  ft.)  No.  2  round-point,  and  a  spoon  or  scoop, 
with  about  an  8-ft.  handle,  in  addition  to  which  digging-bars  and 
pick- axes  are  provided  as  required;  usually  in  ordinary  digging 
a  pick-axe  and  a  digging-bar  to  each  two  men  will  be  all  that  is 
needed.  Under  general  conditions  a  man  will  line  out  his  hole 
around  the  stake  and  work  down  2  ft.,  3  ft.,  or  even  4  ft.,  as  far  as 
the  diameter  of  the  hole  will  permit,  with  the  short-handled  No.  2, 
and  will  not  have  to  use  the  spoon  at  all  in  this  distance;  then 
for  the  remainder  of  the  hole,  the  long-handled  shovel  and  the 
spoon  are  employed  in  the  usual  manner.  Where  poles  with  a 
large  butt  diameter  are  to  be  set,  the  holes  can  often  be  dug  for 
the  entire  distance  with  a  short-handled  shovel,  the  digger  often 
preferring  to  get  into  the  hole  and  do  it  this  way  rather  than  to 
use  a  spoon,  and  it  is  a  good  policy  to  make  this  manner  of 
digging  a  rule,  where  conditions  will  allow  its  use.  as  it  is  better 
and  more  rapid. 

In  setting  poles,  or  to  be  more  exact,  in  raising  them,  the  usual 
method  employed  is  piking,  though  on  long  lines  through  fairly 
level  country,  and  especially  along  highways,  a  gin-wagon  will 
often  do  the  work  more  cheaply.  The  number  ol  men  required 
for  piking-in  average  cedar  poles  is  given  in  Table  VII  as  follows: 

6 


82  TRANSMISSION  LINE  CONSTRUCTION 

TABLE    VII.— CREWS    REQUIRED    FOR    RAISING   POLES    WITH 

PIKES 

Pole  length  30  ft.,  4  pikers,  1  jinny-man,  1  man  at  butt. 
Pole  length  35  ft.,  5  pikers,  1  jinny-man,  1  man  at  butt. 
Pole  length  40  ft.,  6  pikers,  1  jinny-man,  1  man  at  butt. 
Pole  length  45  ft.,  8  pikers,  1  jinny-man,  1  man  at  butt. 
Pole  length  50  ft.,  8  pikers,  1  jinny-man,  1  man  at  butt. 
Pole  length  55  ft.,  9  pikers,  1  jinny-man,  2  men  at  butt. 
Pole  length  60  ft.,  10  pikers,  1  jinny-man,  2  men  at  butt. 

While  data  are  given  for  poles  up  to  60  ft.  it  is  not  very  often 
that  lines,  using  poles  over  40  ft.  as  standard,  employ  piking  to 
raise  their  poles.  The  number  of  men  given  in  Table  VI  is  that 
which  has  been  found  to  give  the  most  economical  results, 
though  a  man  more  or  less  in  the  crew  will  frequently  be  en- 
countered; the  figures  given  represent  general  practice,  based 
upon  cedar  poles  and  good  pikers;  as  piking  is  heavy  work,  the 
men  should  be  selected  with  this  point  in  mind  and  the  cost  per 
pole  for  raising  will  often  be  reflected  by  the  judgment  exercised 
in  selecting  the  crew.  In  piking,  the  raising  and  setting  costs  of 
a  pole  are  merged  and  costs  are  usually  given  for  the  whole  opera- 
tion; in  gin-wagon  work,  the  two  steps  can  be  more  readily 
separated. 

The  cost  of  raising  and  setting  7-in.  top,  35-ft.  northern  cedars 
for  a  typical  line  in  the  Middle  West,  built  in  late  summer  and 
early  fall,  averaged  about  39  cents  per  pole;  the  crew  of  five 
pikers  at  $2,  a  jinnyman  at  $2,  a  buttman  at  $2  and  a  foreman 
at  $4  per  ten-hour  day,  working  at  setting  about  three-quarters 
of  the  time  and  helping  the  diggers  the  rest  of  the  day,  erected 
on  an  average  thirty-five  poles  per  day;  these  poles  were  set  with 
cross-arms  on  and  the  pikers  were  ordinary  unskilled  laborers; 
the  soil  was  a  sandy  clay  and  all  holes  were  trenched  about  1  ft. 

In  Engineering-Contracting  for  Feb.  5,  1908,  figures  are  given 
for  the  building  of  a  short  line  (74  poles  set)  of  30-ft.  to  33-ft. 
chestnut  poles  with  5-in.  to  9-in.  tops;  seven  groundmen  at  $1.50, 
one  lineman  at  $2.50,  and  a  foreman  at  $3  per  ten-hour  day  were 
used  in  raising  and  setting,  and  the  cost  per  pole  for  the  same 
was  76  cents,  distributed  as  follows:  Foreman  14  cents,  ground- 
men,  50  cents,  and  lineman  12  cents,  no  charge  for  teaming  being 
noted.  This  cost  is  somewhat  higher  than  usual,  probably  due 
to  the  small  amount  of  work  done. 

A  3-mile  stretch  of  heavy  9-in.  top,  40-ft.  cypress  poles  set  in 
125-ft.  spans  in  sandy  loam  was  piked  in  at  an  average  cost  of 


WOODEN  POLE  CONSTRUCTION  83 

about  95  cents  each;  these  poles  were  set  without  cross-arms, 
and  the, work  was  carried  on  in  early  springtime. 

Under  average  conditions  such  as  will  be  encountered  in  work 
involving  25  miles  to  50  miles  of  line,  in  the  Middle  West  with 
sandy  loam,  light  clay,  or  black  soil,  7-in.  top,  35-ft.  cedar  poles 
can  be  set  with  pikes  at  an  average  cost  for  labor  of  45  cents;  8-in. 
top,  35-ft.,  at  50  cents,  7-in.  top,  40-ft.,  at  50  cents;  8-in.  top,  40-ft., 
at  55  cents,  and  7-in.  top,  45-ft.  poles  at  about  65  cents.  These 
figures  are  based  upon  results  obtained  in  practice  with  men  at 
$2  per  ten-hour  day  and  foreman  at  $3.50  to  $4  per  diem,  for 
work  through  fairly  well-settled  country,  where  the  men  can  be 
boarded  not  more  than  a  mile  or  two,  on  an  average,  from  the 
location  of  the  work.  For  heavy  clay  soil  the  costs  will  be  about 
10  to  30  per  cent,  higher,  and  if  the  construction  work  be  car- 
ried on  in  the  winter  time  or  the  early  spring  months,  the 
average  cost  per  pole  will  be  from  10  to  25  per  cent,  greater, 
depending  upon  the  latitude. 

Where  the  line  is  built  on  or  closely  parallel  to  a  highway,  or 
through  fairly  level  or  rolling  country  without  a  great  number  of 
fences,  and  in  construction  where  tall  heavy  poles  are  employed, 
such  as  8-in.  top,  45-ft.  or  50-ft.  poles  in  the  cedars,  and  shorter 
in  the  case  of  cypress  and  chestnut,  a  gin  wagon  is  usually  the 
more  economical  method  of  erecting  poles. 

A  gin  wagon  as  usually  built,  consists  of  a  6-in.  top,  30-ft.  to 
35-ft.  cedar  pole,  mounted  upon  a  trunnion  on  the  bed  of  a  stone 
wagon  or  on  a  frame  arranged  to  be  mounted  on  the  running  gear 
of  an  ordinary  heavy  lumber  or  farm  wagon,  in  place  of  the  box, 
one  of  the  latter  type  being  shown  in  Fig.  40;  where  the  amount  of 
work  under  construction  warrants  the  purchase  of  a  complete 
outfit,  wagon  and  all,  a  stone  wagon  or  similar  rig  with  underslung 
bed  is  preferable;  the  gin  pole  itself  is  arranged  for  raising  and 
lowering  with  blocks  or  a  small  crab,  and  space  is  left  at  the  head 
end  for  stowing  ballast;  guy  ropes  are  also  usually  arranged  for  in 
cases  where  the  lift  may  be  heavier  than  will  be  taken  care  of 
by  the  ballast.  The  use  of  a  gasoline  engine-driven  crab  has 
been  suggested  for  the  raising  of  the  poles,  but  this  is  generally 
done  by  unhooking  the  hauling  team  and  using  them  for  that 
purpose. 

In  Fig.  41,  a,  6,  c,  d,  is  illustrated  a  patented  gin  wagon  that 
seems  to  embody  most  of  the  features  desirable  in  a  gin  wagon; 
it  will  be  noted  that  it  is  arranged  with  an  A-frame  mast,  if  it 


84 


TRANSMISSION  LINE  CONSTRUCTION 


may  be  called  that,  provided  with  extension  legs,  so  that  most 
of  the  thrust  is  transmitted  to  the  ground  directly  instead  of 
through  the  wheels,  securing  better  leverage  and  at  the  same 
time  ensuring  much  greater  transverse  stability  than  in  an 
ordinary  wagon;  this  apparatus  is  arranged  to  fit  on  any  ordinary 
farm  or  work  wagon,  and  is  designed  so  that  it  may  be  readily 
dismantled  for  shipment  from  place  to  place.  This  outfit  is 
quoted  at  about  $175  however,  whereas  the  one  shown  in  Fig.  40 
cost  only  about  $60. 

Cost  data  for  raising  poles  with  a  gin  wagon  are  not  very 


FIG.  40. — Erecting  poles  with  gin  wagon. 

abundant;  many  companies  that  employ  them  not  having 
segregated  their  costs,  or  having  let  the  work  by  contract,  know 
only  the  total  costs.  A  line  of  about  20  miles  of  9-in.  top,  40-ft. 
cypress  poles,  set  partly  on  public  highways  and  partly  among 
line  fences  in  well-settled  rolling  country,  was  erected  with  a 
gin  wagon  at  an  average  of  forty  poles  a  day,  with  a  maximum 
of  eighty-seven  in  one  nine-hour  day,  the  latter  record  being 
made  on  a  stretch  where  the  line  was  built  at  the  side  of  a 
straight  level  road;  a  gin  wagon  with  a  28-ft.  gin  mounted  on  a 


WOODEN  POLE  CONSTRUCTION  85 


FIG.  41a. — Gin  wagon. 


FIG. 


86  TRANSMISSION  LINE  CONSTRUCTION 

frame  set  on  the  running  gear  of  an  ordinary  wagon  was  used. 
With  this  rig,  which  required  guys,  four  groundmen  at  $2  a  day, 
one  lineman  at  $2.75,  besides  team  and  teamster,  who  also 
provided  the  running  gear  of  the  wagon,  at  $4  a  day,  the  labor 
cost  per  pole  erected  but  not  set,  on  a  basis  of  forty  poles  per 
day,  was  37  cents. 

With  the  Matthews  pole  erector,  shown  in  Fig.  41,  the  manu- 
facturers claim  that  an  average  of  from  forty  to  fifty  poles,  any 
length  up  to  50  ft.  can  be  set  in  one  day,  with  a  crew  of  two  line- 
men and  a  teamster;  in  a  test  cited,  the  wagon  was  stationed  125 
ft.  away  from  a  hole  with  the  rig  headed  away  from  it,  and  the 
gin  wagon  was  brought  into  place  and  the  pole  dropped  into  the 
hole  in  six  minutes.  From  the  writer's  experience  with  gin- 
wagon  setting,  where  the  conditions  are  such  that  this  method  of 
raising  poles  would  be  adopted,  an  average  of  forty  to  fifty  poles 
a  day  can  be  maintained  with  a  wagon  of  a  type  similar  to  the 
Matthews;  the  saving  of  an  erection  wagon  varies  with  the 
amount  of  labor  required  to  handle  it,  and  the  design  that  will 
be  the  most  economical  in  this  regard  will  generally  be  the  most 
efficient. 

Assuming  an  average  of  forty-five  poles,  say  8-in.  top,  40-ft. 
cedars,  set  per  day  with  a  gin  wagon  requiring  a  crew  of  two 
linemen  at  $2.75  a  day  with  team  and  teamster  at  $4,  the  labor 
cost  per  pole  for  raising  will  be  about  21  cents;  the  cost  per  pole 
for  setting  in  sand,  sandy  loam,  or  black  soil,  with  a  crew  con- 
sisting of  a  foreman  at  $3.50  and  five  groundmen  at  $2  a  day, 
will  be  about  30  cents,  making  a  total  labor  cost  of  51  cents  for 
the  poles  raised  and  set.  With  heavy  poles  of  greater  length, 
the  saving  over  piking  will  be  more  marked. 

In  the  Electrical  World  for  Aug.  1,  1908,  figures  are  given  for 
the  raising  of  a  line  of  45-ft.  poles  with  a  gin  wagon,  a  maximum 
of  eighty-six  poles  being  raised  in  a  ten-hour  day  with  a  crew 
of  one  groundman  and  the  teamster  handling  the  wagon;  it 
must  be  assumed  in  this  case  that  the  groundman  was  able  to 
remove  the  sling  from  the  pole  by  climbing  the  gin  pole,  as  this 
part  of  the  work  is  where  a  lineman  is  usually  employed.  The 
wagon  used  in  this  work  was  very  good,  amounting  practically 
to  a  stiff-leg  derrick  erected  on  an  underslung  wagon-bed;  it 
was  long-coupled,  using  a  long  bed,  and  carried  ten  bags  of 
gravel  for  ballast,  this  being  used  in  place  of  the  ordinary  pig 


WOODEN  POLE  CONSTRUCTION  87 

iron,  etc.,  for  ease  in  shifting  when  it  was  desired  to  handle  the 
load  from  the  side  of  the  wagon. 

In  general,  as  has  been  noted  before,  the  gin  wagon  can  show 
great  economy  over  piking  where  the  poles  are  tall  and  heavy 
and  merits  greater  use  than  it  is  given  in  general  line  construc- 
tion work;  even  where  light  poles,  such  as  7-in.  top,  3o-ft.  poles 
are  used,  a  saving  can  often  be  effected  where  conditions  are 
such  that  the  wagon  can  be  hauled  along  easily  and  without 
too  much  delay  on  account  of  fences,  steep  slopes,  detours  in 
crossing  creeks,  ravines,  etc.;  along  roads,  where  too  many  trees 
are  not  encountered,  there  is  no  reason  why  a  good  gin-wagon 
outfit  cannot  average  sixty  poles  raised  in  a  ten-hour  day, 
especially  if  a  bonus  system  of  payment  be  put  into  effect. 

In  setting  poles,  that  is,  the  straightening-up,  lining-in  and 
back-filling  work  after  the  pole  has  been  raised,  four  groundmen 
with  about  16-ft.  pikes,  one  groundman  with  cant-hooks  on 
the  butt  and  the  foreman,  are  all  that  will  be  required  for  an 
ordinary  35-ft.  or  40-ft.  line;  where  taller  poles  are  to  be  set,  one 
or  two  extra  men  will  be  required;  where  it  is  desired  to  speed 
up  the  setting  work,  this  gang  after  lining-in  the  pole  and  filling 
and  tamping  in  enough  dirt  to  hold  it  solid,  can  leave  it  for  a 
crew  of  four  men  to  complete.  In  lining-in  poles,  an  experi- 
enced eye  in  directing  this  part  of  the  work  is  essential  to  give 
the  line  the  trim,  clean  appearance  that  always  goes  hand  in 
hand  with  good  workmanship;  a  line  that  may  be  set  with  the 
poles  a  trifle  out  o?  line  will  have  the  tops  pulled  over  as  soon  as 
the  wire  is  strung  and  will  not  only  present  an  untidy  appear- 
ance, but  will  start  out  under  a  handicap  of  unbalanced  strains. 
Again,  where  the  alignment  of  the  line  is  good  but  where  the 
tamping  has  been  pooily  done,  the  line  is  liable  to  be  raked  over 
by  a  heavy  wind  and  likewise  appear  in  a  poor  light;  the  old 
rule  of  using  "one  lazy  shoveler  to  three  good  tampers"  is  still 
good. 

In  all  line  construction,  extraordinary  conditions  are  met 
with  which  must  have  special  treatment,  such  as  right-angle 
turns,  branch  taps,  transpositions,  etc.;  this  matter  is  discussed 
in  detail  in  Chapter  VIII,  but  mention  may  be  made  here  with 
particular  reference  to  general  considerations  that  should  be 
taken  into  account  in  deciding  upon  any  special  construction. 

As  a  rule,  any  special  work  that  may  be  required  in  wooden 
pole  work  can  be  built  more  economically  of  wood  than  of  steel; 


88  TRANSMISSION  LINE  CONSTRUCTION 

the  reason  is  that  in  the  first  place  the  pound  cost  and  trans- 
portation charges  on  any  special  structures  of  which  only  a  few 
are  required,  will  be  exceedingly  high,  and  in  the  second  place 
the  work  of  assembling  and  erecting  them  will  devolve,  in  all 
probability,  upon  a  crew  unaccustomed  to  this  class  of  work, 
and  the  ultimate  cost  of  the  structures  in  place  will  usually 
greatly  exceed  that  of  wooden  structures.  In  the  case  of  long 
river  crossings,  etc.,  where  much  special  material  for  even  the 
wooden  structures  would  have  to  be  ordered,  steel  towers  may 
be  more  economical,  and  there  often  will  arise  cases  where  only 
steel  structures  can  be  used.  The  point  to  be  emphasized, 
however,  is  this:  Wherever  it  is  possible  to  make  use  of  the 
standard  line  material,  such  as  poles,  cross-arms,  pins,  etc.,  at 
about  the  same  cost  as  the  material  for  steel  or  concrete  con- 
struction, the  labor  cost  of  erecting  wooden  structures  will, 
as  a  general  thing,  be  so  much  less  than  that  of  erecting  isolated 
steel  towers  that  the  lower  first  cost,  in  view  of  the  remainder 
of  the  construction  being  of  wood,  will  offset  the  advantages 
of  permanency  and  reliability  possessed  by  the  steel  construction. 


CHAPTER   V 
STEEL    POLE   CONSTRUCTION 

With  the  great  increase  in  transmission  line  building  in  the 
past  few  years,  there  has  been  an  insistent  demand  for  supports 
of  greater  permanency,  of  lesser  liability  to  damage  or  destruc- 
tion, and  of  greater  possibilities  for  economy  in  the  higher  vol- 
tages than  wooden  poles,  but  which  still  would  not  require  the 
extensive  field  work  nor  demand  the  right-of-way  space  of 
structural  towrers.  For  the  long,  heTavy,  extra  high-voltage 
lines  of  great  capacity,  where  heavy  expenditures  for  private 
right-of-way,  private  patrol  roads,  etc.,  may  be  warranted  by 
the  general  magnitude  of  the  whole  undertaking,  the  steel  tower 
line  has  the  field  practically  to  itself,  but  for  lines  of  medium 
capacity  operating  under  potentials  up  to  50,000  or  60,000  volts, 
poles  of  either  steel  or  reinforced  concrete  in  250-ft.  to  350-ft. 
spans,  will  show  great  possibilities  and,  when  due  consideration  is 
given  to  the  comparative  right-of-way  costs,  field  expenses  and 
ultimate  life,  will  usually  be  found  more  economical  than  the 
light  tower  construction  that  would  be  required  for  the  same 
conditions. 

In  the  line  of  steel  poles,  we  have  various  structural  designs 
of  the  latticed  girder  type,  tubular  poles  and  several  patented 
designs,  such  as  the  diamond  and  the  tripartite,  previously 
described  in  Chapter  III.  Of  these  four  general  types,  the 
tubular  and  the  diamond  have  each  points  of  weakness  in  that 
they  do  not  have  the  weight  efficiency  of  a  structural  pole,  and 
that  they  are  totally  enclosed,  making  it  impossible  to  maintain 
the  protection  of  the  inner  surfaces;  to  the  best  knowledge  of 
the  writer  there  are  no  regular  transmission  lines  utilizing  either 
of  these  types  in  the  United  States,  and  they  will  not  be  dis- 
cussed further  as  a  factor  in  steel  pole  construction  for  high- 
tension  lines;  in  Europe,  and  also  somewhat  in  Canada,  the 
tubular  pole  has  been  used  to  some  extent  in  transmission  work, 
but  as  a  general  thing  its  employment  has  been  limited  to  trolley 
construction. 


90  TRANSMISSION  LINE  CONSTRUCTION 

What  little  steel  pole  line  has  been  built  in  this  country  has 
employed  either  a  three-  or  a  four-post  (in  most  cases  the  latter) 
angle-iron  latticed  riveted  structure,  or  a  pole  of  the  tripartite 
design.  Though  there  have  been  many  instances  where  short 
stretches  of  line  have  been  built  in  connection  with  other  types 
of  construction,  as  at  city  ends  of  transmission  lines,  etc.,  the 
development  of  the  possibilities  of  steel  pole  construction  in 
America  is  far  behind  that  in  Europe. 

The  best-known  installations  of  latticed  pole  construction  in 
this  country  are  the  lines  of  the  Sanitary  District  of  Chicago,  the 
New  York  Central  &  Hudson  River  Railroad  and  the  Long 
Island  Railroad. 

The  Sanitary  District  poles  are  60  ft.  long  overall,  set  6  ft.  deep 
in  concrete,  and  carry  two  three-phase  circuits  of  nineteen-strand 
aluminum  cable  equivalent  to  No.  000  copper,  operating  at 
44,000  volts,  on  standard  pin-type  insulators;  as  shown  in  Fig.  42, 
the  poles  are  arranged  with  two  arms,  a  top  arm  12  ft.  long  and  a 
bottom  arm  18  ft.  long,  for  two  circuits  normally,  but  recently 
another  circuit  was  added  by  the  use  of  two  suspension-type 
insulators  swung  one  on  each  side  of  the  bottom  arm,  midway 
between  the  original  conductor  supports,  in  connection  with  a 
pin-type  insulator  attached  at  the  peak  of  the  pole  in  place  of 
the  ground  wire  clamp.  At  the  top  these  poles  are  14  in.  square 
and  at  the  base  42  in.  on  a  side;  they  weigh  complete  about  4000 
Ib.  and  are  designed  to  carry  a  load  of  5000  Ib.  applied  at  the  top; 
normally  they  are  spaced  about  350  ft.  apart.  As  will  be  noted 
they  are  of  angle-iron  construction,  riveted  and  assembled  with 
two  field  splices,  making  the  sections  about  20  ft.  long;  the 
structures  are  galvanized  throughout. 

The  New  York  Central  poles,  illustrated  in  Fig.  43,  are  built 
with  the  top  straight  for  about  7  1/2  ft.  and  then  the  corner  posts 
follow  a  parabolic  curve  from  that  point  to  the  base;  the  standard 
height  of  the  pole  above  the  concrete  base  is  29  ft.  1  in.  As 
given  by  the  Engineering  News  for  June  14,  1906,  they  are 
built  up  of  four  3-in.  X3-in.  X5/16-in.  angles,  single  laced  with 
2  1/4-in.Xl  l/2-in.x3/16-in.  angles  and  weigh  about  1340  Ib. 
each;  the  standard  pole  measures  14  in.  square  at  the  top  and 
2  ft.  10  in.  at  the  base;  wooden  arms  are  used  and  two  three- 
phase  11,000-volt  circuits  are  carried;  the  standard  spacing  on 
tangent  is  150  ft. 

These  poles  were  not  galvanized,  but  in  assembling  them  in 


STEEL  POLE  CONSTRUCTION 


91 


FIG!  42. — Sanitary  district — steel  pole  construction. 


92 


TRANSMISSION  LINE  CONSTRUCTION 


the  shops,  all  contact  surfaces  were  painted  with  New  York 
Central  red  lead  paint,  and  upon  completion  of  the  shopwork 
they  were  given  one  coat  of  the  same;  in  the  field  they  were  given 
two  heavy  coats  of  black  asphaltum  varnish. 

The  Long  Island  Railroad  poles,  shown  in  Fig.  44,  are  some- 
what similar  in  design  to  those  of  the  New  York  Central,  except- 
ing that  the  corner  posts,  or  main  members,  are  not  curved  and 

the  top  is  rectangular  instead  of  square; 
the  top  of  this  design  measures  6  in.  X 
11  in.  and  the  base  about  3  ft.  4  in. 
square;  the  poles  are  about  39  ft.  4  in. 
in  height  above  the  base  to  which  they 
are  bolted,  which  is  of  concrete  about 
4  1/2  ft.  to  5  ft.  square  and  8  ft.  deep. 
As  given  by  the  Street  Railway  Journal 
for  June  9,  1906,  these  poles  are  de- 
signed to  carry  twenty-four  250,000  circ. 
mil  cables  at  the  top,  with  eight  500,000 
circ.  mil  feeders  lower  down,  in  150-ft. 
spans  on  tangent;  in  making  the  cal- 
culations the  maximum  wind  pressure 
was  assumed  as  13.5  Ib.  per  square  foot 
of  the  projected  area  of  the  cable.  The 
standard  poles  were  built  with  3-in.  X3- 
in.  x3/8-in.  angles  for  the  main  mem- 
bers, and  for  angles,  and  other  heavy 
work,  poles  with  3-in.  X3-in.-X7/16-in. 
posts  were  used;  the  poles  were  single 
laced  with  angles  and  were  painted  in- 
stead of  galvanized. 

In  this  design  as  in  that  of  the  New 
York  Central,  wooden  arms  were  used. 
They  were  attached  to  the  poles  by 
passing  them  through  the  pole  and 
clamping  them  down  on  two  angles,  one  on  each  side  of  the  pole, 
by  means  of  U-bolts  over  the  top;  with  the  clamp  pin  designed 
by  W.  N.  Smith  for  this  work,  in  connection  with  this  method 
of  attaching  cross-arms,  no  boring  of  the  arms  at  all  was 
required. 

In  construction  utilizing  the  tripartite  steel  pole,  the  lines  of  the 
United   States    Reclamation   Service   in   connection   with   the 


FIG.  43. — New    York 
Central  pole. 


STEEL  POLE  CONSTRUCTION 


93 


Section  at  B-B 

FIG.  44. — Long  Island  R.  R.  poles. 


94 


TRANSMISSION  LINE  CONSTRUCTION 


distribution  of  power  from  the  Roosevelt  Dam  development  in 
Arizona,  and  the  Pueblo  line  of  the  Anglo-Mexican  Hydro- 
Electric  Company  of  Mexico  City,  Mexico,  are  typical. 

The  poles  used  in  the  original  Reclamation  Service  work  came 
in  three  lengths  with  three  different  weights  in  each  length,  the 
data  on  the  various  designs  being  as  follows: 


Length,  ft.      Weight,  Ib. 

Diameter  top,  in. 

Diameter  butt,  in. 

40 

1100 

7.5 

18.5 

40 

1183 

7.5 

22.0 

40 

1230 

7.5 

28.0 

45 

1230 

7.5 

18.5 

45 

1310 

7.5          23.0 

45 

1400 

7.5 

30.0 

50 

1370 

7.5 

19.0 

50 

1520 

7.5           23.0 

50 

1680 

7.5 

32.5 

These  weights  are  for  the  bare  pole;  the  cross- arming  for  the 
single  circuit  construction  weighed  130  Ib.  in  addition  to  the 
above,  and  the  same  for  carrying  a  double  circuit,  450  Ib.  The 
poles  are  all  built  up  of  a  special  U-section  bar,  2  13/32  in.  wide 
X 2  3/16  in.  deep  X 3/8  in.  thick,  weighing  6.4  Ib.  per  lineal  foot, 
arranged  in  the  form  of  an  equilateral  triangle  and  bound 
together  with  malleable  iron  collars  and  spreaders.  The  double- 
circuit  line,  shown  in  Fig.  45,  built  with  the  above-mentioned  poles 
set  in  concrete  to  a  depth  of  4  ft.,  4  1  /2  ft.  and  5  ft.  respectively  for 
the40-ft.,  45-ft.  and  50-ft.  poles,  carries  the  two  three-phase  cir- 
cuits of  83,000  cir.  mil  copper  cable  in  spans  of  from  300  ft.  to  400ft. 
The  cross-arm  construction  of  this  installation  is  unusual  in  that 
U-bars,  1/4  in.  thick,  are  used  instead  of  the  ordinary  angle-iron 
section.  This  is  one  of  the  largest  individual  installations  of 
steel  poles  in  the  United  States,  a  total  of  2700  poles  being 
reported  to  have  been  installed  in  connection  with  same,  in 
both  low-  and  high-tension  work. 

The  line  of  the  Anglo-Mexican  Hydro-Electric  Company  was 
built  with  poles  43  ft.  7  in.  long  from  cap  to  butt,  and  provided 
with  a  ground-wire  support,  formed  by  the  prolongation  of  one 
of  the  main  U-members,  extending  about  6  ft.  above  the  top  of 
the  pole;  the  diameter  of  the  top  of  this  design  is  7  1/2  in.  and 


STEEL  POLE  CONSTRUCTION  95 


FIG.  45. — Tripartite  pole. 


96  TRANSMISSION  LINE  CONSTRUCTION 

that  of  the  butt,  about  18  in.  The  conductors  are  arranged  in 
a  48-in.  triangle  with  three  malleable-iron  bracket-arms,  and  a 
telephone  circuit  is  carried  on  malleable-iron  brackets  below. 
The  main  U-members  of  the  pole  are  2  5/32  in.  wide  X  2  1/16  in. 
deep  X 1/4  in.  thick;  the  pole  complete  with  equipment  weighs 
about  1050  lb.,  and  set  to  a  depth  of  5  ft.  in  concrete  bases  carries 
three  No.  1  copper  line  conductors  and  two  No.  8  telephone  wires 
in  285-ft.  to  350-ft.  spans. 

In  Europe,  especially  in  Italy,  Switzerland  and  Germany,  steel 
pole  construction  has  been  developed  to  a  much  greater  extent 
than  in  this  country.  The  general  practice  in  Europe,  however, 
appears  to  tend  to  the  use  of  lighter  supports  placed  more  closely 
together  than  here;  the  structures  themselves  are  generally  of  a 
latticed  type,  though  I-beam  sections,  tubular  poles,  and  a  design 
somewhat  similar  to  the  tripartite,  are  also  used.  There  the 
practice  has  also  been  to  build  the  lines  on  the  elastic  or  flexible 
system,  with  anchor  structures  at  quite  close  intervals,  whereas 
here  one  design  is  used  throughout,  with  the  possible  exception 
of  cases  where  heavy  angles  are  to  be  turned. 

One  of  the  late  European  installations,  the  Lauckhammer  line, 
notable  in  that  it  is  the  first  110,000-volt  transmission  to  be  con- 
structed in  Europe,  employs  a  type  of  structure  that  may  well  be 
classed  as  a  pole,  though  on  account  of  the  high  voltage,  heavier 
poles  and  longer  spans  are  used  than  in  ordinary  practice.  As 
described  in  the  Electrical  World  for  Oct.  28,  1911,  the  structures, 
illustrated  in  Figs.  46  and  47,  are  60  ft.  to  65  ft.  in  height  above  the 
ground,  and  are  built  of  four  angle-iron  main  members  with  a 
lacing  of  lighter  angles;  the  line  is  constructed  on  the  flexible 
system  with  intermediate  poles  about  28.5  in.  on  a  side  at  the 
ground  line  and  anchor  structures  about  51.2  in.  The  poles  are 
spaced  from  500  ft.  to  650  ft.  apart,  and  carry  two  three-phase 
circuits  of  83,000  circ.  mil  seven-strand  copper,  with  a  100,000 
circ.  mil  steel  ground  wire  at  the  top.  As  will  be  noted  from  the 
illustrations,  a  novel  cross-arrangement  was  devised,  reducing  the 
torsional  moment  on  the  structure;  a  grounding  scheme  is  also  pro- 
vided for  in  the  shape  of  an  extra  arm  arranged  to  catch  and 
ground  a  conductor  should  an  insulator  break.  The  spacing 
between  conductors  is  only  5  ft.  9  in.,  with  a  distance  between 
circuits  of  about  9  ft.  10  in.,  whereas  the  general  American  practice 
for  this  voltage  and  span  has  been  to  provido  a  conductor  clear- 
ance of  from  8  ft.  to  10  ft. ;  it  is  likely,  however,  that  climatic  and 


STEEL  POLE  CONSTRUCTION 


97 


mechanical  considerations  determined  this  as  the  most  suitable. 
Another  German  line,  built  from  Homburg  to  Crefeld  and 
other  points,  will  be  of  interest  as  showing  general  Continental 
practice  more  closely;  as  described  in  the  Electrotechnische 
Zeitschrift  for  Dec.  14,  1911,  this  line,  which  is  constructed  on  the 
flexible  system,  uses  intermediate  poles  built  up  of  two  latticed 
channels,  and  strain  poles  of  four-post  latticed-angle  construction. 
These  poles  were  bolted  to  concrete  bases,  in  a  manner  similar  to 


14B-15-5 


~L  100-100-10 


FIGS.  46  AND  47. — Lauckhammer  steel  poles. 


the  Long  Island  Railroad  poles,  instead  of  being  set  into  them,  as 
is  the  method  most  usually  employed.  The  poles  are  a  little  less 
than  37  ft.  long,  and  carry  two  three-phase  20,000-volt  circuits 
in  spans  of  40  meters  to  80  meters. 

This  type  of  construction  appeals  to  the  writer  as  a  natural 
combination  of  the  good  features  of  both  steel  tower  and  wooden 


98  TRANSMISSION  LINE  CONSTRUCTION 

pole  construction  with  an  elimination  of  many  of  the  undesirable 
ones.  The  moderate  length  of  span  allows  the  use  of  fairly  short 
structures,  and  with  voltages  below  50,000  to  60,000  volts, 
moderate  spans  ought  to  work  out  very  economically.  One 
drawback  to  the  use  of  steel  poles  in  this  country  has  been  the 
lack  of  proper  judgment  as  to  the  load  for  which  poles  should  be 
designed;  the  same  people  who  will  erect  wooden  lines  with 
almost  any  kind  of  a  pole  will  make  all  sorts  of  extraordinary 
assumptions  when  they  come  to  figure  what  they  should  require 
their  steel  poles  to  carry.  According  to  Mr.  Semenza,  as  noted 
in  his  paper  in  the  1904  Transactions  of  the  American  Institute  of 
Electrical  Engineers,  the  same  condition  prevailed  in  Europe  in 
the  early  development  of  steel  pole  structures  there;  this  char- 
acteristic, moreover,  is  not  confined  to  steel  pole  design,  but 
as  discussed  under  Steel  Tower  Design  in  a  later  chapter,  is  also  a 
condition  that  prevails  in  other  types  of  construction. 

As  far  as  the  present  development  of  steel  pole  construction 
in  this  country  and  abroad  is  concerned,  the  general  overall 
lengths  of  poles  usually  employed  as  standard,  appear  to  be  from 
35  ft.  to  45  ft.;  the  poles  are  usually  assembled  complete  in  one 
length  in  the  shop,  except  in  special  cases;  the  weights  for 
average  high-tension  service  in  these  lengths  will  run  from  800  Ib. 
to  2500  Ib..,  varying  much  for  the  same  service,  with  the  climatic 
conditions  in  different  parts  of  the  country. 

The  cost  of  riveted  latticed  poles,  with  one  shop  coat  of  paint, 
will  run  from  31/2  cents  to  51/2  cents  per  pound,  depending 
upon  the  size  of  the  order  and  the  particular  design,  together 
with  condition  of  the  steel  market;  tubular  poles  will  run  from 
2  3/4  cents  to  3  1/4  cents,  and  tripartite  poles  from  23/4  cents 
to  4  cents  per  pound.  All  prices  are  f.o.b.  the  shops. 

As  steel  poles  are  generally  assembled  complete,  with  the  excep- 
tion of  cross-arms,  in  the  shops,  they  call  for  about  the  same  load- 
ing for  shipment  as  do  wooden  poles;  as  in  the  case  of  the  latter, 
poles  over  40  ft.  in  length  require  double  car  loading;  the  mini- 
mum car-load  weight  for  steel  poles  is,  however,  usually  a  little 
greater  than  that  for  wooden  poles. 

The  handling  of  steel  poles  requires  the  exercise  of  a  little 
more  care  and  discretion  than  in  th,e  case  of  wood  in  order  not 
to  scrape  off  paint  or  galvanizing,  and  to  avoid  kinking  or  buckling 
any  of  the  members;  the  unloading  of  a  shipment  of  steel  poles  can 
be  handled  very  easily  by  using  a  light  25-ft.  or  30-ft.  cedar  pole 


STEEL  POLE  CONSTRUCTION  99 

as  a  gin  pole,  or  in  the  case  of  a  load  of  long  poles,  two  gin  poles, 
erected  on  the  side  of  the  car  opposite  to  which  the  unloading  is 
to  take  place  and  raked  so  as  to  bring  their  tops  fairly  near  to  the 
center  line  of  the  car;  skids  are  then  built  up  to  the  side  of  the  car 
so  that  after  a  pole  is  raised  clear  of  the  balance  of  the  load,  it 
can  be  pulled  over  and  lowered  to  the  skids  by  means  of  a  tag 
line,  at  the  same  time  slacking  off  on  the  gin-pole  blocks;  the 
poles  may  then  be  worked  along  this  unloading  skid-way  to 
their  proper  position  in  the  yard.  No  data  are  available  as  to 
the  unloading  costs  on  any  particular  steel  pole  for  transmission 
work,  but  from  personal  experience  in  unloading  other  types  in 
the  above  manner,  the  writer  believes  that  for  a  40-ft.  pole 
weighing  from  1500  Ib.  to  2000  lb.,  the  cost  per  pole  for  unload- 
ing should  not  exceed  30  cents  to  35  cents. 

The  arrangement  and  the  system  of  handling  of  poles  in  the 
yard  should  be  the  same  for  steel  poles  as  for  wooden,  and  they 
will  be  loaded  for  distribution  by  means  of  a  gin  pole  or  derrick; 
in  unloading  in  the  field  they  cannot  be  "snaked  off"  as  easily 
as  a  heavy  wooden  pole,  but  by  exercising  a  little  care  and  in- 
genuity, they  can  be  unloaded  without  any  trouble;  with  very 
heavy  poles  it  may  be  necessary,  and  will  probably  be  good 
economy  in  the  case  of  lighter  ones  also,  to  rig  up  a  light  tripod 
or  to  employ  a  gin  wagon  in  the  field  to  unload  the  wagons. 
The  distribution  costs  cannot  be  estimated  with  any  degree  of 
accuracy  without  knowing  the  characteristics  of  the  particular 
design  of  pole  used.  No  figures  are  available  for  the  distribu- 
tion costs  per  pole  where  steel  poles  have  been  hauled  out  by  team 
under  conditions  that  ordinarily  prevail  in  transmission  line 
construction,  but,  basing  an  estimate  upon  ordinary  four-post 
latticed-angle  poles,  40  ft.  long  and  weighing  about  1500  lb. 
each,  an  ordinary  team  can  easily  haul  three  of  these  over  average 
country  roads  and  make  two  10-mile  round  trips,  or  a  total 
daily  mileage  of  20  miles.  With  teams  at  $4  a  day,  a  yard  fore- 
man at  $3  and  a  helper  at  $2  per  ten-hour  day,  and  a  man  in  the 
field  to  help  unload  at  $2  a  day,  the  cost  for  distribution  under 
these  conditions  with  six  or  eight  teams  working  ought  not  to 
exceed  75  cents  or  85  cents  per  pole.  Where  a  long  stretch  of  the 
line  is  to  be  served  from  one  distribution  point,  a  man  should  be 
stationed  at  both  the  near  and  the  far  ends,  and  the  teams  sent 
out  alternately  on  long  hauls  and  short  hauls;  it  is  obvious  that 


100  TRANSMISSION  LINE  CONSTRUCTION 

the  more  teams  employed,  up  to  a  certain  point,  the  lower  the 
yard  and  field  expenses  per  pole  delivered. 

Steel  poles  are  generally  set  in  concrete  bases,  and  the  usual 
practice  is  to  make  the  depth  of  set  one-tenth  the  overall  length 
of  the  pole,  for  transmission  work;  the  Sanitary  District  poles 
which  are  60  ft.  overall,  are  set  6  ft.  deep,  and  the  Franklin 
Steel  Company  also  uses  this  ratio  in  its  work;  the  minimum 
depth  of  set  in  any  case  is  usually  4  ft.  The  size  of  the  concrete 
base  naturally  depends  upon  the  dimensions  of  the  butt  of  the 
pole  and  upon  the  character  of  the  soil  in  which  the  poles  are  to 
be  set,  and  is  usually  specified  by  the  manufacturer.  Where 
poor  setting  is  encountered,  it  is  well  to  calculate  the  bearing  area 
required  at  the  base,  when  the  pole  is  under  maximum  load,  and 
to  make  sure  that  sufficient  base  width  is  provided. 

The  holes  for  setting  steel  poles  are  usually  dug  with  more 
care  than  in  wooden  pole  work,  and  to  a  specified  size,  as  in 
most  cases  the  sides  of  the  holes  are  the  forms  for  the  concrete, 
and  where  the  digging  is  not  closely  observed,  more  concrete 
than  is  needed  will  be  required.  For  the  bases,  a  1:3:6  or  a 
1:3  1/2  :7  mixture  of  cement,  sand,  and  coarse  gravel  or  crushed 
stone  will  be  satisfactory  and  should  be  placed  fairly  sloppy;  the 
concrete  base  is  usually  brought  up  6  in.  or  so  above  the  ground 
level  and  the  top  sloped  a  little  so  as  to  shed  water. 

The  cost  of  digging  holes  for  steel  pole  construction  will  run 
the  same  as  that  for  wooden  pole  work,  under  the  various  condi- 
tions, except  in  so  far  as  the  necessity  for  cleaner  cut  holes  may 
slow  down  the  work  a  little. 

Steel  poles  are  set  in  the  same  manner  as  wooden  poles,  by 
means  of  pikes,  gin  wagon  or  gin  pole;  for  average  poles,  weighing 
up  to  2500  Ib.  or  so,  an  ordinary  gin  wagon  rigged  as  for  wooden 
pole  work  is  very  satisfactory;  for  heavier  poles  a  special  heavy 
rigged  gin  wagon  or  a  gin  pole  will  be  required;  light-  and  medium- 
weight  poles  can  be  piked  in  very  readily,  using  a  pike  provided 
with  a  U-  or  V-shaped  point  instead  of  a  'spike,  in  connection 
with  a  regular  jinny  adapted  to  the  section  of  the  pole  to  be 
raised.  Where  a  gin  wagon  can  be  used  it  is  generally  the  most 
rapid  and  economical  method  of  raising  poles,  excepting  in  the 
case  of  light  ones;  the  gin-wagon  or  gin-pole  methods  of  erecting 
have  in  many  cases  an  important  advantage  over  piking,  in  that 
there  is  no  danger  of  gouging-out  or  caving-in  the  walls  of 


STEEL  POLE  CONSTRUCTION  101 

the  holes  in  setting,  and  so  increasing  the  subsequent  cost  of 
concreting. 

After  raising,  the  poles  must  be  braced  or  guyed  in  position  for 
lining-in  and  after  being  set  in  alignment,  must  be  left  with  the 
braces  or  guys  in  place  until  the  poles  have  been  concreted  and 
the  concrete  has  set  sufficiently  to  allow  their  removal;  in  the 
setting  of  the  tripartite  poles  used  in  the  Salt  River  Reclamation 
work,  as  described  in  the  Electrical  World  for  March  30,  1911,  four 
guys  were  attached  to  a  pole,  and  after  its  erection,  it  was  straight- 
ened up  by  means  of  these,  and  lined-in  with  plumb-bobs  located 
over  reference  stakes  set  by  the  surveying  party  for  that  purpose; 
after  being  lined-in  the  pole  was  held  in  place  by  pulling  up  the 
four  guys  with  a  pair  of  light  blocks,  fastening  them  to  steel 
stakes,  and  then  leaving  them  for  the  concreting  gang. 

The  lining-in  of  poles  set  in  long  spans  can  possibly  be  done 
very  easily  by  the  use  of  reference  stakes,  but  this  requires  a 
location  survey,  and  for  lines  employing  moderate  spans,  there 
is  no  reason  why  steel  poles  cannot  be  lined-in  by  sighting  back 
to  the  poles  previously  set,  as  in  wooden  construction. 

For  tall  poles,  guys  will  probably  always  have  to  be  used  to 
hold  the  poles  in  position  during  the  concreting  of  the  bases  and 
until  they  are  hard  enough  to  hold,  but  where  short  poles  are 
employed,  it  may  often  be  possible  to  block  the  poles  at  the 
ground  line  with  stones  or  wedges,  leaving  enough  room  to  pour 
the  concrete,  and  bring  the  concrete  up  around  them,  thus 
saving  the  labor  of  going  back  and  removing  guys  after  the 
concrete  has  set. 

The  concreting  of  the  bases  should  be  carried  on  immediately 
after  the  poles  are  set;  general  information  as  to  mixture  and 
consistency  of  the  concrete  has  already  been  noted;  the  work  can 
be  done  by  a  crew  of  two  men  with  team  and  teamster,  equipped 
with  a  light  sheet-metal  mixing  "board"  or  a  small  hand- 
turned  machine  mixer.  In  pouring  the  concrete,  care  should  be 
taken  not  to  get  any  dirt  mixed  with  it,  and  a  trough  or  chute 
should  be  provided  for  this  purpose;  the  concrete  should  be 
tamped  so  as  to  work  it  well  around  the  pole.  The  material  for 
the  bases  will  be  carried  along  in  the  wagon,  with  another  team 
on  the  road  hauling  from  the  base  of  supplies  and  replenishing 
the  same  as  needed. 

As  to  the  crewr  required  for  the  erection  and  setting  of  steel 
poles,  its  average  daily  progress  on  the  work  depends  naturally 


102  TRANSMISSION  LINE  CONSTRUCTION 

upon  the  weight,  length  and  design  of  the  pole  in  question;  for 
average  work  through  farming  country  with  sandy,  sandy-loam, 
light  gravel,  or  black  soil,  the  digging,  raising  and  setting, 
namely,  the  erection  of  the  structures  complete,  for  a  line  of 
40-ft.  latticed  poles  weighing  about  1800  lb.,  will  require  a  crew 
consisting  of  about  the  following:  one  general  foreman,  four 
diggers,  one  sub-foreman,  five  groundmen  with  gin  wagon,  one 
team  and  man  for  same,  two  men  with  team  and  teamster  for 
the  concrete  work,  and  one  man  with  team  and  teamster  remov- 
ing guys  from  previous  day's  work  and  hauling  material  for 
concrete  work;  this  crew  ought  to  average  from  ten  to  twenty 
poles  erected  a  day.  On  this  basis  for  conditions  obtaining  in 
the  Middle  West,  where  foremen  will  cost  $3.50  to  $4,  sub-fore- 
men, $2.50  to  $3,  groundmen  $2  and  teams  with  teamster,  $4  per 
ten-hour  day,  the  labor  cost  per  pole  erected  will  run  from 
$2.10  to  $4.20. 

On  the  Salt  River  Reclamation  Service  work,  with  the  labor 
and  climatic  conditions  prevailing  in  Arizona,  from  eight  to 
twelve  poles  were  set  each  day  with  a  crew  of  twenty-two  men. 
On  a  line  of  steel  poles  built  in  Colorado,  the  poles  varying  in 
overall  length  from  25  ft.  to  45  ft. ,  with  a  35-f  t.  pole  weighing  about 
510  lb.  as  standard,  the  contract  price  for  erecting  the  poles  was 
$6.50  per  pole;  the  poles  were  set  about  4  1/2  ft.,  in  concrete,  the 
material  for  which  was  furnished  by  the  contractor. 

On  the  Sanitary  District  work,  the  cost  of  setting  the  60-ft. 
poles  weighing  about  4000  lb.  each  is  given  at  $55  average;  in 
this  work  18  miles  of  the  total  30-mile  length,  was  rock  setting. 

The  general  mile  cost  of  steel  pole  construction  will,  as  a  rule, 
not  be  much  greater  than  that  of  wooden  pole  line;  in  many  cases 
it  is  less  and  where  the  comparison  is  made  with  treated  poles 
there  is  very  little  difference  in  the  Middle  West  between  the  first 
costs  of  the  two  types  of  construction.  In  connection  with 
hydro-electric  work  of  moderate  capacity,  steel  pole  line  will  un- 
doubtedly in  the  near  future  take  the  place  of  wooden  pole  lines 
just  as  concrete  dams  are  superseding  wooden  dains.  With  the 
development  of  transmission  systems  radiating  from  a  large 
central  town  to  the  smaller  towns  and  villages  surrounding, 
where  the  capacity  and  operating  voltages  of  the  lines  will  be 
moderate,  the  steel  pole  has  another  great  field. 


CHAPTER  VI 
STEEL  TOWER  CONSTRUCTION 

Steel  towers  are  the  unquestioned  standard  for  trunk  lines  of 
any  great  capacity  operating  under  the  higher  voltages,  and  in  the 
past  few  years  they  have  been  utilized  in  practically  all  suhc 
installations  of  any  magnitude.  With  the  development  of  steel 
tower  work,  two  distinct  types  or  systems  of  construction  have 
been  evolved,  the  rigid  and  the  flexible  or  elastic. 

Aa  previously  noted,  the  former  consists  in  proportioning  all 
line  towers,  excepting  those  at  angle  points,  long-span  crossings, 
etc.,  to  resist  the  same  strains  in  all  directions,  while  in  the  flex- 
ible system,  two  kinds  of  line  structures  are  used,  classed  as 
anchor  or  strain  towers,  and  intermediate  towers,  the  former 
designed  for  heavy  strains  both  longitudinally  and  transversely 
and  the  latter,  built  with  only  two  posts  or  main  members, 
arranged  to  resist  the  same  transverse  strain  as  the  anchor 
towers  but  with  practically  no  strength  in  a  direction  parallel 
to  the  line,  and  designed  to  allow  considerable  distortion  or 
deflection  due  to  unbalanced  conductor  pull,  without  any  per- 
manent set. 

There  is  a  variation  from  each  of  the  foregoing  general  types 
of  tower  construction;  in  the  rigid  construction,  while  it  is  the 
general  practice  to  use  all  towers  on  tangent  of  the  same  strength, 
several  lines  of  a  capacity  demanding  heavy  conductors  have 
employed  structures  of  a  design  much  heavier  than  standard, 
at  1-mile  or  2-mile  intervals,  to  serve  the  same  purpose  as  storm- 
guyed  poles,  that  is,  to  prevent  cumulative  failure  of  structures 
on  a  long  tangent;  these  towers  have  been  designed  to  carry  the 
dead-end  pull  of  all  conductors,  with  sometimes  a  heavy  wind  in 
addition.  In  the  flexible  system,  likewise,  we  have  a  variation 
from  the  design  of  a  light  structure  acting  as  a  prop  under  the 
conductors,  in  the  type  which  is  known  as  semi-flexible  con- 
struction; a  semi-flexible  structure,  as  its  name  implies,  is  a 
tower  of  greater  strength  in  the  direction  of  the  line  than  that  of 
the  type  first  brought  out.  The  flexible  system  is  primarily  the 

103 


104  TRANSMISSION  LINE  CONSTRUCTION 

result  of  an  attempt  to  lower  the  total  cost  of  structures  for  a 
line,  and  in  principle  amounts  to  providing  props  to  keep  in  the 
air,  a  line  that  is  anchored  solidly  at  each  end  of  long  stretches 
with  plenty  of  slack  in  between,  the  props  being  braced  against 
transverse  strains  and  held  in  place  longitudinally  by  a  heavy 
ground  wire  and  the  conductors  themselves,  transmitting  longi- 
tudinal strains  to  the  anchor  towers  at  intervals  of  a  mile  or  so. 

The  flexible  system  is  based  upon  the  fact  that  with  equal 
spans  on  both  sides  of  a  structure,  the  longitudinal  strains  are 
ordinarily  balanced;  if  a  conductor  breaks,  the  tower,  under  the 
influence  of  the  unbalanced  pull  of  this  conductor,  assuming  that 
it  is  tied-in  or  clamped  solidly  so  as  to  be  the  same  as  dead-ended, 
is  distorted  and  pulls  around  at  the  top  until  the  decreasing 
tension  in  the  broken  conductor,  say  in  the  case  of  a  single-circuit 
structure,  is  balanced  by  the  pull  of  the  ground  wire  and  the 
other  two  conductors  transmitted  from  the  anchor  tower  theo- 
retically, though  the  resistance  of  the  intermediate  supports 
helps  also.  As  a  small  increase  in  the  length  of  wire  in  a  span 
reduces  the  tension  materially,  it  is  apparent  that  the  deflection 
at  the  top  need  not  be  considerable  to  effect  a  balance;  ordinarily 
it  is  not  more  than  6  in.  or  8  in.,  and  as  the  structures  are  usually 
designed  for  a  safe  distortion  of  two  or  three  times  this,  there  is 
no  permanent  deformation.  This  type  of  construction  has 
worked  out  very  satisfactorily  in  Europe,  and  with  attention  to 
the  balancing  of  the  spans,  the  employment  of  a  heavy  ground 
wire,  and  with  the  use  of  moderate  span  lengths,  there  is  no 
reason  why  it  should  not  meet  with  the  same  approval  here. 
Proper  use  of  head-guys  at  intervals  as  needed,  in  between  the 
anchor  structures,  ought  also  to  allow  the  employment  of 
unequal  spans  to  take  advantage  of  favorable  topographical 
conditions  without  dire  results  from  unbalanced  pull  under  vary- 
ing temperature  conditions,  where  this  variation  in  the  con- 
struction may  be  permissible. 

The  structures  for  flexible  construction  are  as  a  general  thing 
made  up  complete  and  riveted  in  the  shop,  and  shipped  assembled 
with  the  exception  of  the  cross-arms;  they  have  therefore  the 
advantage  of  lower  field  costs  than  towers  of  the  rigid  type  in 
the  elimination  of  the  assembling  work,  and  as  usually  con- 
structed with  the  main  members  of  channel-iron,  are  also  much 
simpler  to  erect.  They  possess  another  feature  that  gives  them 
an  advantage  over  light-tower  construction,  in  that  the  section 


STEEL  TOWER  CONSTRUCTION  105 

of  their  members  is  greater  and  they  have  a  minimum  of  small 
section  members  at  the  best,  so  that  the  effect  of  corrosion  in  a 
moderate  degree  is  not  so  serious  a  matter  to  them  as  it  is  to  a 
light-built  rigid  tower. 

In  the  general  matter  of  the  design  of  any  type  of  tower,  for  a 
given  size  and  number  of  conductors,  and  length  of  spans,  under 
similar  topographical  and  climatological  conditions,  there  is  a 
great  difference  in  opinion  among  engineers  as  to  what  strains 
the  tower  and  its  attachments  shall  be  designed  to  resist,  and  to 
some  extent  as  to  what  factor  of  safety  shall  be  allowed.  One 
engineer  will  often  specify  test  loads  or  make  assumptions  of 
conditions  to  be  met,  that  another  engineer  will  declare  absurd; 
the  fact  of  the  matter  is,  that  the  difference  in  opinion  is  often 
due  to  the  point  of  view  that  each  takes  in  the  light  of  his  past 
experience  in  other  parts  of  the  country,  and  so  we  sometimes 
find  sleet-proof  construction  in  localities  where  sleet  has  never 
been  known  to  occur,  and  light  construction  through  a  territory 
where  sleet  is  a  regular  occurrence. 

Again,  outside  of  assumptions  as  to  what  weather  conditions 
may  be  encountered,  which  latter  can  usually  be  quite  clearly 
determined  by  referring  to  the  Government  climatological  records 
of  the  particular  locality  for  a  period  of  thirty  to  fifty  years  back, 
comes  the  question  as  to  what  condition  of  loading  due  to  the 
line  conductors  should  be  combined  with  the  strains  set  up  by 
sleet  and  high  winds,  etc.  Some  engineers  will  want  a  tower  that 
will  stand,  say,  for  a  single-circuit  structure,  the  wind  and  sleet 
load  as  noted,  in  combination  with  the  dead-end  pull  produced  by 
the  breakage  of  any  two  of  the  conductors,  while  others  will 
figure  that  for  a  single-circuit  tower,  the  unbalanced  loading  due 
to  the  severing  of  only  one  conductor  will  need  to  be  reckoned 
with;  still  others  will  require  a  tower  to  stand  only  the  maximum 
wind  and  sleet  load,  without  the  combination  of  unbalanced 
strains  due  to  broken  conductors,  each  engineer  backing  his  own 
personal  opinion. 

In  commenting  upon  this  feature  of  tower  design,  D.  R. 
Scholes  of  the  Aermotor  Company  says  in  his  article  on  tower 
design,  Transactions  American  Institute  of  Electrical  Engineers 
for  1G07,  page  1257,  "Each  engineer  seems  to  have  a  different 
set  of  natural  conditions  to  meet.  The  severity  of  his  assumptions 
seems  to  depend,  generally,  on  how  much  money  his  company 
can  afford  to  spend  on  towers."  From  the  inconsistency  dis- 


106  TRANSMISSION  LINE  CONSTRUCTION 

played  in  the  specifications  under  which  tower  structures  are 
purchased,  it  certainly  does  seem  that  engineers  have  no  inclina- 
tion to  trifle  with  nature  if  they  can  possibly  "play  safe." 

In  general,  following  the  recommendations  of  the  engineering 
societies,  it  is  now  the  practice  in  localities  where  sleet  is  known 
to  occur,  to  assume  a  1/2-in.  coating  of  sleet  all  around  a  con- 
ductor with  a  wind  pressure  of  8  Ib.  per  square  foot  on  the  pro- 
jected area  of  the  sl^eet-covered  conductor,  and  a  wind  pressure 
on  the  surface  of  the  tower  structure  of  13  Ib.  per  square  foot; 
then  in  combination  with  the  foregoing  weight  and  wind  load, 
the  structure  is  designed  to  withstand  the  unbalanced  pull  due 
to  one  or  more  broken  conductors. 

The  allowance  for  broken  conductors,  it  appears  to  the  writer, 
should  depend  somewhat  upon  the  generating  capacity  of  the 
system;  in  the  case  of  lines  with  a  small  generating  capacity  that 
could  not  hold  up  a  heavy  current  on  short  circuit  for  any  length 
of  time,  there  is  not  so  much  danger  of  burning  off  conductors 
upon  the  breaking  down  of  the  insulation  as  where  the  station 
capacity  is  relatively  great,  and  from  the  writer's  experience,  a 
line  wire  is  burned  off  very  seldom  where  the  total  capacity  of 
the  system  is  only  a  few  thousand  kilowatts.  Furthermore, 
when  a  conductor  does  burn  or  break  off,  the  unbalanced  pull 
will  often  slip  it  through  the  tie  or,  in  the  case  of  a  suspension- 
type  insulator,  will  pull  that  over  and  throw  slack  into  the 
adjacent  spans,  materially  reducing  the  pull  and  shock  also,  and 
this  feature  should  be  taken  into  consideration. 

The  manner  of  drawing  up  specifications  for  tower  structures 
varies,  in  that  some  engineers  give  ultimate  test  loads  and  others 
give  the  working  loads  and  specify  a  certain  safety  factor;  the 
latter  method  is  certainly  preferable.  The  factor  of  safety  called 
for  is  usually  two  or  three  for  the  structure  as  a  whole,  under  the 
maximum  conditions  of  load,  and  for  the  fittings,  either  three  or 
four;  with  the  assumptions  as  to  what  the  maximum  load  is  to 
be,  as  severe  as  they  usually  are,  a  safety  factor  of  two  for  the 
structure  and  of  three  for  the  fittings  is  in  the  estimation  of  the 
writer  ample.  Where  no  sleet  is  assumed,  as  on  the  Pacific 
coast,  and  where  very  high  winds  are  encountered,  the  higher 
safety  factors  may  be  assumed. 

In  the  design  of  towers  for  a  flexible  system,  the  intermediates 
are  built  to  stand  the  same  loading  and  conditions,  as  outlined 
in  the  foregoing,  but  only  in  a  direction  transverse  to  the  line; 


STEEL  TOWER  CONSTRUCTION  107 

in  a  longitudinal  direction,  their  strength  is  generally  determined 
by  the  size  of  the  members  necessarily  provided  to  take  care  of 
the  transverse  load;  the  anchor  towers,  located  usually  at  1-mile 
intervals,  are  designed  to  resist  the  wind  and  weight  load  result- 
ant in  combination  with  the  dead-end  pull  if  all  the  conductors 
should  be  severed;  the  factors  of  safety  should  be  the  same  as 
for  other  types. 

The  height  of  structure  that  is  required  for  a  given  circuit  and 
size  of  conductors  in  average  level  country  depends  upon  the 
number  of  towers  used  per  mile,  the  minimum  allowable  clearance 
to  ground,  the  material  of  which  the  conductors  are  composed, 
and  the  natural  conditions  as  to  sleet,  temperature,  etc.,  imposed 
by  the  particular  locality  in  which  the  line  is  to  be  built. 

As  a  general  thing,  from  seven  to  twelve  towers  per  mile  has 
been  the  standard  American  practice,  the  longer  span  construc- 
tion naturally  being  employed  in  the  higher-voltage  lines;  based 
upon  the  height  of  the  lowest  conductor  above  ground,  as  is  the 
standard  in  rating  structures  of  this  type  in  America,  and  using 
copper  wire,  45-ft.  to  50-ft.  towers  have  been  used  generally  for 
the  longer  spans,  40-f t.  to  45-ft.  for  the  medium,  and  35-f t.  to  40-ft. 
for  lines  employing  eleven  or  twelve  structures  per  mile.  Under 
similar  conditions  as  to  temperature  range,  etc.,  aluminum  con- 
ductors will  require  a  higher  structure  for  the  same  minimum 
clearance  to  ground  than  copper,  and  steel-strand  a  lower  one. 

The  weights  and  prices  of  towers  vary  naturally  with  the 
conditions  imposed  and  the  design,  but  for  a  single-circuit 
60,000-volt  line  up  to  say  No.  00  copper  conductors,  40-ft. 
towers  will  weigh  from  1600  Ib.  to  2500  lb.;  50-ft.,  from  1800  Ib. 
to  3000  lb.  and  60-ft,,  from  2200  lb.  to  3500  lb.;  40-ft.  double- 
circuit  towers  for  the  same  general  conditions  will  weigh  from 
2200  lb.  to  3500  lb.;  50-ft.,  from  2600  lb.  to  4200  lb.  and  60-ft., 
from  3200  lb.  to  5000  lb.;  the  price  per  pound  for  towers  will 
vary  with  the  market,  the  design,  and  the  size  of  the  order,  from 
3  1/4  cents  to  4  1/4  cents  f.o.b.  shops,  for  galvanized  structures, 
with  prices  dropping  below  the  foregoing  minimum  at  times; 
painted  structures  will  cost  from  1/2  cent  to  1  cent  less  per  pound 
than  the  above. 

There  has  been  much  discussion  in  the  past  as  to  the  compara- 
tive values  of  galvanizing  and  painting  in  the  protection  of  a 
tower  from  corrosion,  but  it  is  now  the  general  practice  to  specify 
galvanizing  irrespective  of  the  relative  values  of  the  two  methods, 


108  TRANSMISSION  LINE  CONSTRUCTION 

in  order  to  avoid  the  trouble  and  operating  difficulties  incident 
to  repainting.  If  galvanizing  is  properly  done,  especially  by  the 
sherardizing  process,  it  is  of  unquestioned  value,  but  many  cases 
of  inferior  work  are  encountered  and  even  where  the  original 
protection  is  satisfactory,  its  value  may  be  greatly  reduced  by 
careless  field  work,  as  for  instance  in  the  assembling  of  a  tower, 
where  drifting  is  required,  the  galvanizing  at  the  bolt  holes  is 
destroyed,  and  in  the  case  of  light  members,  rusting  at  these 
points  will  soon  reduce  the  strength  of  the  section  to  an  unsafe 
value.  In  the  case  of  tower  designs  that  do  not  involve  the  use 
of  a  great  number  of  small  members,  so  that  the  cost  of  repainting 
will  be  prohibitive,  there  is  still  a  field  for  paint  as  a  protection; 
this  applies  particularly  to  the  heavy-section  structures  used  in 
flexible  tower  work. 

While  discussing  protection,  it  will  be  well  to  take  note  of  the 
matter  of  minimum  thickness  of  metal  for  the  various  members 
of  a  structure;  many  light  towers  have  been  built  with  the  main 
members  only  1/8  in.  thick,  which  in  the  writer's  estimation 
does  not  give  sufficient  lee-way  against  the  effects  of  corrosion 
and  a  thickness  of  not  less  than  3/16  in.  and  preferably  1/4  in. 
ought  to  be  specified  for  main  members,  with  1/8  in.  to  3/16  in. 
for  minor  members. 

In  the  consideration  of  the  various  proposed  designs  of  struc- 
tures for  a  line,  they  should  not  only  be  studied  from  the  stand- 
point of  co,st,  loading,  and  material,  but  also  as  to  the  rapidity 
and  economy  with  which  the  field  work  on  them  can  be  carried 
out.  There  is  a  marked  difference  in  the  cost  of  assembling  and 
raising  a  tower  built  on  a  simple  girt  and  diagonal  plan  over 
that  of  a  type  involving  the  use  of  many  small  truss  angles,  and 
where  the  conditions  of  loading  will  allow  the  use  of  either  at 
about  the  same  price,  the  former  will  give  more  satisfactory 
results  in  place. 

Any  tower  should  be  so  designed  that  the  parts  can  be  tied 
up  into  convenient  bundles  of  similar  members  weighing  not 
more  than  about  100  Ib.  each,  for  ease  in  shipping  and  in  handling 
in  the  field;  all  small  parts  that  cannot  be  readily  bundled  should 
be  boxed  with  the  bolts.  All  bundles  should  be  securely  wired 
together  and  tagged  with  the  erection  number  or  letter  for  those 
particular  parts  and  with  the  size  and  type  of  structure  for  which 
they  are  intended;  it  is  also  a  good  policy  to  call  for  the  stenciling 
of  this  information  on  one  or  two  of  the  pieces  in  each  bundle  of 


STEEL  TOWER  CONSTRUCTION  109 

similar  parts;  boxes  or  kegs  containing  bolts,  etc.,  should  be 
marked  with  the  list  of  parts  contained  and  the  tower  height  to 
which  they  belong. 

As  tower  shipments  come  in,  they  cannot  usually  be  unloaded 
for  distribution  directly  from  the  cars  and  it  is  necessary  to  pro- 
vide a  systematic  means  of  unloading  and  arranging  the  mate- 
rial, so  as  to  avoid  delay  and  confusion  when  the  teams  are  to 
be  loaded  in  hauling-out  for  distribution  later  on.  The  most 
satisfactory  method  usually  is  to  seek  a  level  place  along  a  side- 
track, where  teams  can  come  in  easily,  and  lay  out  spaces  for 
each  kind  of  tower,  large  enough  to  accommodate  segregated 
piles  of  the  various  bundles  making  up  the  parts  of  each  size  of 
structure  in  a  group;  then  series  of  two  or  three  stakes,  extending 
4  ft.  to  6  ft.  out  of  the  ground  should  be  driven  so  as  to  form  pens 
into  which  the  bundles  of  similar  members  may  be  piled,  leaving 
all  the  parts  of  a  certain  size  of  structure  laid  out  so  as  to  be 
readily  accessible,  and  the  material  for  the  different  kinds  of 
towers  isolated  in  groups.  This  is  similar  to  the  method  used 
in  storing  steel  for  reinforced  concrete  building  construction, 
and  works  out  well;  the  stakes  between  the  piles  will  be  marked 
with  the  erection  mark  for  the  parts  enclosed.  The  bundles 
should  be  laid  out  endwise  to  the  driveway,  and  if  the  groups 
can  be  arranged  on  either  side  of  a  lane  through  which  the  team 
may  drive,  this  will  be  of  assistance  in  loading. 

In  distributing,  the  wagons  should  be  provided  with  ordinary 
boxes  or,  preferably,  racks  with  full  bottoms  so  that  there  will 
be  no  possibility  of  the  smaller  bundles  working  through.  In 
construction  through  agricultural  country  where  it  will  be 
necessary  to  use  teams  from  the  small  towns  along  the  line  as 
well  as  those  of  farmers  living  in  the  territory  traversed,  close 
supervision  will  usually  be  required  to  get  the  right  tower  to 
the  right  stake.  In  average  medium  voltage  and  capacity  line 
work,  under  conditions  obtaining  in  the  Middle  West,  two  towers 
per  load  can  be  hauled  over  ordinary  country  roads. 

As  each  teamster  is  loaded  and  is  ready  to  start,  the  yard 
foreman  will  give  him  a  slip  naming  the  individual  stakes  to 
which  the  towers  comprising  his  load  are  to  go,  checking-out 
against  him  by  name  on  a  progress  sheet  or  time  book,  the 
numbers  he  is  to  haul  to,  in  order  to  identify  him  in  case  of  poor 
delivery.  It  is  also  a  good  policy  to  place  a  man  in  the  field  to 
assist  in  the  unloading,  but  primarily  to  see  that  the  towers  go 


110  TRANSMISSION  LINE  CONSTRUCTION 

where  they  are  supposed  to  go  and  that  the  full  number  of  bun- 
dles is  delivered  at  each  location;  where  a  man  is  so  used  in  the 
field  to  check  the  distribution,  each  teamster  should  be  required 
to  return  to  the  yard  foreman  for  checking  on  his  tally  sheet, 
the  hauling  slip  previously  mentioned,  duly  O.  K.'d  by  the 
field  man,  giving  a  definite  progress  report  on  the  distribution 
work.  A  foreman  at  $2  to  $2.25,  who  will  also  do  all  the  time- 
keeping for  the  distribution  work,  besides  checking  material  on 
to  the  loads  and  directing  the  teamster,  with  two  men  at  $1.75 
or  $2  a  day,  can  take  care  of  the  yard  work. 

Based  upon  hauling  two  towers  per  load  an  average  distance 
of  5  miles  or  6  miles  per  trip,  with  teams  at  $4  a  day,  a  yard  crew 
as  already  noted  and  a  man  in  the  field  at  $2  a  day,  the  labor  cost 
for  distribution  will  run  from  $2  to  $2.50  per  tower;  these 
figures  of  course  will  not  apply  to  the  heavier  structures,  but 
are  based  upon  the  fact  that  on  average  country  roads  a  fair 
team  can  haul  4000  Ib.  to  6000  Ib.  as  a  load  and  make  two  round 
trips  of  10  miles  or  12  miles  each  per  diem.  As  noted  under  the 
topic  of  distribution  for  wooden  poles,  the  teams  should  be  sent 
out  in  twos  or  threes,  so  as  to  assist  each  other  in  case  of  acci- 
dent or  of  bad  roads,  hills,  etc. 

Actual  cost  figures  on  a  short  line  of  double-circuit  tower 
construction  for  a  line  about  4.2  miles  long,  give  the  cost  of  dis- 
tributing the  steel  for  these  4400-lb.  structures  as  $2.25  per 
tower  average,  with  teams  at  56  1/4  cents  and  unskilled  labor 
at  28  cents  per  hour;  in  the  Electrical  World  for  Sept.  9,  1911, 
the  cost  of  hauling  towers  for  the  Amherst  Power  Company  line 
is  given  at  $4.28  each,  with  16  cents  as  the  cost  of  delivering 
the  anchors  for  each  structure. 

In  most  cases  the  anchors  for  towers  are  a  channel-iron  or 
similar  plate  attached  to  the  end  of  a  6-ft.  or  7-ft.  stub  of  angle 
iron,  for  the  lighter  structures,  or  in  the  case  of  tall,  heavy 
towers  a  built-up  grillage  of  steel  is  used,  bolted  to  an  angle-iron 
leg  in  the  same  way  as  in  the  lighter  work;  in  many  cases  con- 
crete foundations  are  placed  for  the  line  structures  also,  but  in 
most  instances  they  are  used  only  at  points  of  unusual  strain. 

A  typical  anchorage  of  the  grillage  type,  showing  the  method 
on  installing  the  same  is  illustrated  in  Fig.  48;  a  typical  concrete 
foundation,  consisting  in  anchor  bolts  embedded  in  concrete 
footings,  in  the  same  manner  as  for  a  piece  of  machinery,  is 
shown  in  Fig.  49.  These  anchors  are  the  standards  used  in  the 


STEEL  TOWER  CONSTRUCTION 


111 


Ontario  Hydro-Electric  Power  Commission  work,  the  earth 
setting  being  used  ordinarily  and  the  concrete  foundation  in 
the  case  of  angle,  dead-end,  high  towers,  etc. 

In  most  tower  work,  the  anchor  stubs  are  shipped  in  advance 
of  the  main  structures  and  are  set  before  the  rest  of  the  material 
arrives.  The  method  of  setting  anchors,  practically  universal 


_  initiation  of 
field  stones 


FIG.    48. — Standard    earth    setting    of    anchors — Ontario    Hydro-Electric 
Power  Commission  work. 

now,  is  to  employ  a  light,  but  rigid,  angle-iron  templet  to  which 
the  anchor  stubs  may  be  bolted  and  rigidly  held  at  the  correct 
level,  spacing  and  slope. 

The  towers  are,  or  should  be,  staked  out,  as  described  in  a 
previous  chapter,  with  a  hub-stake  for  locating  the  center  of 
the  tower  and  a  lining  or  reference  stake  10  ft.  or  15  ft.  ahead  on 
line,  by  means  of  which  the  anchors  can  be  set  square  with  the 
line,  though  very  often  only  the  center  stake  is  located  and  the 


112 


TRANSMISSION  LINE  CONSTRUCTION 


anchors  are  lined-in  by  means  of  the  adjacent  location  stakes; 
this  latter  method  is  fairly  accurate  where  the  towers  are  quite 
close  together,  but  does  not  ensure  the  workmanlike  job  that 
the  first  method  does. 

The  general  system  often  employed  in  anchor  setting  in  earth 
is  as  follows,  where  the  soil  is  sand,  sandy  loam,  light  gravel, 
or  similar  average  digging,  and  where  the  work  is  being  carried  on 
in  the  summer  time.  Two  crews  are  used,  the  first  one  consist- 


Elevation 

FIG.  49. — Concrete  anchors — Ontario  Hydro-Electric  Power 
Commission  work. 


ing  of  a  sub-foreman  and  three  men,  provided  with  a  "  dummy" 
templet  of  wood  and  digging  tools,  and  the  second  crew,  of  the 
digging  foreman  and,  for  average  conditions  as  described,  about 
eight  men,  equipped  with  the  setting  templet,  shovels  and  tamp- 
ing tools 

The  first  crew  with  the  "dummy"  or  digging  templet,  made 
up  with  light  1-in.  X  4-in.  or  6-in.  stuff,  as  shown  in  Fig.  50,  locates 
the  tower  corner  points  by  centering  the  templet  over  the  hub 
by  means  of  the  hole  in  the  center,  and  then  lining-in  the  mark 


STEEL  TOWER  CONSTRUCTION 


113 


or  tack  at  "  A,"  with  the  center-hole  and  the  reference  or  lining 
stake  set  by  the  surveying  crew  a  short  distance  ahead  on  line; 
with  the  stub  positions  located,  the  templet  is  removed  and  each 
man  blocks  out  a  hole  and  digs  to  the  required  dimensions. 

In  digging  for  towers  set  on  gentle  slopes,  the  low  holes  should 
be  dug  full  depth  and  the  others  to  the  same  level;  where  steep 
slopes  are  encountered,  a  "cut"  and  "crib-fill"  arrangement 
may  have  to  be  used.  Anchor  holes  should  be  dug  so  that  the 
bottom  of  the  anchor  plate  will  rest  on  undisturbed  earth  as  far 
as  is  possible  and  should  always  be  deep  enough  so  that  the 
ground  joint  can  be  covered  by  banking  the  dirt  a  little  around  the 


FIG.  50. — Digging  templet. 

corner  posts,  and  where  towers  are  set  in  tilled  fields  it  is  a  good 
policy  even  to  bring  the  ground  joint  partly  below  the  original 
ground  level,  as  in  the  working  of  the  land,  especially  where  the 
tower  design  is  such  that  there  is  room  to  drive  through  the  tower 
and  the  space  beneath  the  structure  is  under  active  cultivation, 
any  banking  will  soon  be  leveled. 

In  digging  these  holes  a  man  can  ordinarily  work  in  the  hole 
with  a  2-ft.  D-handle  No.  2  shovel,  though  sometimes  it  is  neces- 
sary to  use  a  shovel  with  a  shorter  grip  in  order  to  handle  it 
well  in  the  size  pit  required;  there  is  a  marked  increase  in  the 
output  of  a  digger  working  in  the  hole,  over  that  of  one  working 
on  top  of  the  ground,  using  a  No.  2  as  far  as  possible  and  finish- 

8 


114  TRANSMISSION  LINE  CONSTRUCTION 

ing  up  with  a  spoon.  For  most  towers,  the  size  of  the  holes 
demanded  for  the  proper  setting  of  the  anchors  is  sufficient  to 
allow  a  man  to  work  in  them,  and  if  it  is  not,  they  may  often  be 
economically  dug  a  little  larger  than  necessary  so  as  to  make  the 
same  possible,  as  the  difference  in  the  amount  of  excavation  will 
be  more  than  compensated  for  by  the  increase  in  the  amount  of 
work  done.  In  throwing  out  the  dirt  from  the  hole,  the  same 
should  always  be  cast  outside  of  the  area  enclosed  by  the  tower 
and  preferably  in  a  pile  in  line  with  the  diagonals  of  the  base 
produced ;  in  this  way  the  spoil  will  not  be  in  the  way  of  the  men  of 
the  second  crew  in  handling  the  templet,  and  will  allow  three 
tampers  and  a  shoveler  to  work  at  the  hole  conveniently  in  back- 
filling. 


FIG.  51. — Setting  anchors. 

The  second  crew,  carrying  the  setting  templet,  places  it 
roughly  in  position  over  the  holes,  assembles  the  anchors,  and 
bolts  them  in  place  on  the  templet;  the  templet  is  then  centered 
over  the  tower-hub  and  squared  with  reference  to  the  line  by 
means  of  marks  on  the  templet  and  the  lining  stake  as  previously 
described;  where  the  templet  is  so  constructed  that  the  center 
cannot  be  closely  located,  marks  at  the  middle  of  the  oppo- 
site sides  of  the  templet  will  be  lined-in  with  the  hub  and  refer- 
ence stakes.  As  the  templet  is  lined  in  it  is  also  leveled  up  all 
around,  a  24-in.  carpenter's  level  being  very  satisfactory  for  this 
purpose,  and  then  blocked  securely  in  position;  typical  views  of 
anchor-setting  showing  templets  will  be  noted  in  Figs.  51  and  52. 


STEEL  TOWER  CONSTRUCTION  115 

Before  back-filling  is  commenced,  the  templet  should  be  checked 
by  measuring  the  diagonal  distances,  to  detect  and  correct  any 
tendency  to  rack  into  a  diamond  shape;  with  the  heavy  riveted 
templets,  or  the  elaborate  trussed  types,  this  may  not  be  very 
necessary,  but  with  the  light  bolted  kind  provided  with  rod- 
diagonals,  this  check  should  be  taken. 

With  the  anchors  in  their  correct  position,  two  men  at  each 
corner  commence  filling-in  and  tamping  carefully,  working  the 
dirt  solidly  under  the  anchor  plates  until  all  four  anchors  are 
solidly  backed  up  with  tamped  dirt,  the  holes  being  filled  and 
tamped  evenly  all  over  the  bottom  in  so  doing.  With  all  four 


FIG.  52. — Setting  anchors. 

anchors  properly  bedded,  the  templet  should  be  tried  for  level 
and,  everything  O.  K.,  the  crew  will  split  into  two  gangs  composed 
each  of  three  tampers  and  a  shoveler,  each  gang  taking  an  anchor 
on  the  same  side  of  the  line  and  back-filling  the  hole  complete  and 
then  repeating  the  operation  on  the  other  side.  The  tamping 
should  be  thorough  and  where,  especially  in  the  case  of  structures 
that  will  be  subjected  to  line  strains  a  short  time  after  their 
erection,  it  may  be  deemed  necessary,  water  should  be  used 
to  wet  down  the  back-fill  when  dry  soil  is  encountered. 

Where  the  digging  is  slow,  owing  to  the  kind  of  soil  or  to  frost, 
if  the  work  be  carried  on  at  times  of  the  year  when  it  may  be 
encountered,  an  extra  crew  of  two  or  four  diggers  each  may  be 


116  TRANSMISSION  LINE  CONSTRUCTION 

required  to  follow  up  Crew  No.  1,  and  Crew  No.  2  may  be  in- 
creased in  size  as  may  be  required,  though  the  use  of  too  many 
men  to  one  setting  templet  should  be  avoided;  where  the  total 
crew  is  increased  in  this  way,  Crew  No.  1  would  be  reduced  prob- 
ably to  two  men  only  with  the  digging  templet  and  they  would 
merely  block  out  the  holes  to  a  few  inches  in  depth,  leaving  the 
excavation  to  be  done  by  the  intermediate  crews;  this  would 
probably  also  call  for  an  extra  man  as  sub-foreman  in  general 
charge  of  the  digging,  acting  under  the  direction  of  the  setting 
foreman. 

In  the  work  of  the  Ontario  Hydro-Electric  Power  Commission, 
the  system  followed  in  setting  anchors  was  somewhat  similar  to 
the  above,  two  men  with  the  digging  templet  comprising  the  lead- 
ing crew,  following  which  came  the  diggers,  with  the  setting 
gang  of  twelve  men  and  a  foreman  bringing  up  the  rear. 

In  the  work  just  mentioned  the  anchors  required  a  hole  7 
ft.  6  in.  deep  and  3  ft.  6  in.  square,  and  under  favorable  condi- 
tions five  sets  of  anchors  could  be  set  each  day;  the  labor  cost  on 
standard  footings  set  in  dry  or  damp  soil  was  from  $15  to  $25; 
it  will  be  noted  that  the  depth  of  these  holes  is  about  1  1/2  ft. 
greater  than  is  required  for  towers  used  in  most  installations; 
and  that  the  anchors  were  blocked  around  with  field  stones; 
water  was  also  carried  to  wet  down  the  back-fill. 

On  a  job  in  the  Middle  West  where  digging  was  easy,  the  soil 
being  a  sandy  loam,  the  labor  cost  of  setting  anchors  about  6  ft. 
deep  for  a  line  of  light  40-ft.  and  50-ft.  towers  ran  from  $4  to  $6 
per  tower;  for  setting  in  earth,  with  a  little  concrete  work  in 
places,  the  anchors  for  a  line  of  40-ft.  single-circuit  towers,  the 
Electrical  World  for  Sept.  9,  1911,  gives  a  cost  of  $3.38  per  tower, 
with  excavation  at  $6.91  per  tower;  these  are  contractors  costs 
and  no  information  is  given  as  to  wage  scale,  or  character  of 
soil. 

The  cost  of  setting  concrete  foundations  for  a  line  of  double- 
circuit  40-ft.  standard  towers,  weighing  about  2650  Ib.  each,  is 
given  as  $11  per  set  for  the  standard  line  structures  and  $81 
for  angle  towers;  this  line  was  built  in  the  Middle  West,  where 
labor  costs  about  $2  to  $2.25  per  ten-hour  day.  In  the  West, 
where  the  cost  of  labor  is  very  high,  the  following  costs  of  con- 
crete tower  footings  for  a  4.2-mile  line  of  double-circuit  towers 
weighing  about  4400  Ib.,  will  be  of  interest;  these  are  contractors 
costs  and  do  not  include  his  profit;  the  excavation  for  the  anchors 


STEEL  TOWER  CONSTRUCTION  117 

averaged  $12  per  tower  and  the  concrete,  $31  or  about  $6.45  per 
cubic  yard,  making  a  total  labor  and  concrete  cost  per  set  of 
anchors  of  $43.  The  first  half  of  the  line  was  built  through 
rocky  ground,  but  for  the  remainder  of  the  work  sandy  soil  was 
encountered;  the  unskilled  labor  received  28  cents,  linemen  and 
mechanics,  45  cents,  foremen,  50  cents  and  teams,  56  1/4  cents  per 
hour. 

In  general  there  has  been  little  consistency  shown  in  the  labor 
costs  of  setting  anchors  as  compared  for  instance  with  those  for 
setting  poles,  and  the  inference  is  that  much  of  the  difference 
is  due  to  a  greater  familiarity  on  the  part  of  the  construction 
men  with  the  latter  work. 

The  assembling  of  towers  in  the  field  is  a  phase  of  line  construc- 
tion that  provides  many  opportunities  for  the  development  of  a 
"  system"  of  handling  the  work.  Usually  each  line  job  is  a 
study  by  itself  as  far  as  this  matter  is  concerned,  as  the  tower 
designs  not  only  differ,  but  the  skill  and  intelligence  of  the 
workmen  is  a  variable  quantity. 

The  method  of  carrying  on  the  work  of  assembling  that  appears 
to  give  the  most  satisfactory  result  is  that  of  splitting  up  the  crew 
into  small  gangs,  each  with  its  own  particular  part  of  the  work 
to  perform;  for  instance  in  the  case  of  a  line  of  40-ft.  towers  with 
a  crew  of  fourteen  to  sixteen  men  and  a  foreman,  two  men  will 
be  sent  ahead  to  break  out  bundles,  open  bolt-boxes,  etc.,  and 
then  roughly  lay  out  in  place  the  members  for  the  bottom  face  of 
the  tower,  with  those  for  the  other  three  sides  arranged  system- 
atically in  their  relative  places,  then  four  or  five  men  and  a  sub- 
foreman  will  follow  and  assemble  say  the  upper  half  of  the  struc- 
ture, bolting  everything  pertaining  to  this  part  of  the  structure 
in  place,  but  not  necessarily  drawing  the  bolts  up  tight,  then  the 
next  crew  of  about  the  same  number  of  men  will  arrive  and  com- 
plete the  assembling,  after  which  two  men  will  go  over  the  entire 
structure  and  draw-up  tight  all  bolts  and  fastenings,  leaving  the 
structure  ready  to  erect.  This  system  of  carrying  on  the  work 
allows  each  set  of  men  to  become  more  familiar  with  a  certain 
part  of  the  work  which  naturally  increases  their  efficiency,  and 
again  the  men  are  not  so  liable  to  be  in  each  other's  way,  etc., 
as  when  one  big  gang  goes  to  work  to  assemble  a  tower  by  itself, 
complete.  By  adjusting  the  crews  or  the  amount  of  work  to 
be  done  by  each  gang,  so  that  one  gang  will  naturally  complete 
its  work  in  a  little  less  time  than  the  other  gang  can  its  own,  a 


118  TRANSMISSION  LINE  CONSTRUCTION 


FIG.  53. 


FIG.  54. 


FIG.  55.  FIG.  56. 

Views  showing  the  assembling  of  tower  illustrated  in  Fig.  57. 


STEEL  TOWER  CONSTRUCTION 


119 


spirit  of  rivalry  may  be  worked  up  that  will  make  its  effect 
apparent  on  the  progress  report.  While  the  use  of  two  men  to 
follow  up  the  assembling  gang  and  go  over  and  tighten  up  all 
bolts,  may  possibly  lead  to  a  little  carelessness  on  the  part  of  the 
main  gangs,  which  however  can  easily  be  located  by  noting  the 
part  of  the  tower  where  it  occurs,  it  insures  a  good,  final  inspec- 
tion of  the  work  and  the  saving  of  time  to  the  main  gangs  though 
not  having  to  delay  each  other  in  finishing  the  setting  up  of  a  nut 
in  a  hard  place,  more  than  offsets  the  cost  of  the  extra  men. 


FIG.  57. 

After  setting  up  the  nut  on  a  bolt,  some  companies  will  batter  the 
threads  so  as  to  prevent  the  nuts  from  working  loose;  this  is  a 
good  idea. 

In  Figs.  53,  54,  55  and  56  are  shown  typical  views  of  the  assem- 
bling of  the  tower  illustrated  in  Fig.  57;  this  structure  was  usually 
assembled  in  three  steps,  the  head,  then  the  section  down  as  far 
as  the  long  diagonals  at  the  bottom,  and  then  the  bottom;  in 
Fig.  56  will  be  noted  the  light  gin  pole  used  to  support  the  top 
members  until  the  side  members  were  all  attached,  and  also  the 


120  TRANSMISSION  LINE  CONSTRUCTION 

horse  used  in  working  on  the  top  face.  For  ordinary  assembling 
work,  10-in.  or  12-in.  monkey  wrenches,  a  few  ball-pien  hammers, 
drift-pins,  center-punches,  one  or  two  axes,  5/8-in.  rope  and  a  set 
of  light  blocks,  and  track  wrenches  are  all  the  tools  that  will  be 
required,  with  such  equipment  in  the  way  of  light  ladders,  horses 
and  a  light  gin  pole  arrangement,  etc.,  as  may  be  called  for  by  the 
particular  design  to  be  assembled;  of  these,  the  only  one  that  may 


FIG.  58. — Amherst  Power  Co.'s  tower. 

not  be  generally  familiar  is  the  track  wrench,  which  consists 
merely  in  a  combination  of  an  open-end  wrench  and  a  drift  pin, 
the  jaws  of  the  wrench  being  made  narrow  and  thick  and  the 
shank  forged  into  a  drift  pin. 

The  labor  cost  for  assembling  towers  on  a  line  using  as  standard 
a  50-ft.  tower  with  16-ft.  base  spread  of  the  design  shown  in 
Fig.  57,  was  about  $7.50  each;  this  work  was  carried  on  in  late 
summer  and  fall  under  unfavorable  circumstances;  the  men  were 


STEEL  TOWER  CONSTRUCTION 


121 


quartered  in  camps  and  unskilled  labor  cost  about  $2.50  a  day; 
the  length  of  the  line  was  about  42  miles.  The  assembling  cost 
of  the  towers  for  another  line  of  single-circuit  structures  is  given 
in  the  Electrical  World  for  Sept.  9,  1911,  as  $8.20;  a  cut  of  this 
tower  line  is  given  in  Fig.  58,  and  it  may  be  noted  that  it  was 


FIG.  59. — Single-circuit  tower  used  by  the  Ontario  Hydro-electric  Power 

Commission. 


only  8.5  miles  long;  no  data  is  given  as  to  wage  scale.  The 
single-circuit  tower  shown  in  Fig.  58  is  a  42-ft.  structure,  about 
52  ft.  overall,  with  a  base  spread  of  12  ft.  The  average  cost  of 
assembling  the  single-circuit  towers  of  the  Ontario  Hydro- 
Electric  Power  Commission,  shown  in  Fig.  59,  the  work  being 
carried  on  in  the  summer  time,  is  given  at  $7.35  each. 

In  double-circuit  work,  the  average  cost  per  tower  for  the 


122 


TRANSMISSION  LINE  CONSTRUCTION 


assembling  in  the  Ontario  Hydro-Electric  construction,  is  given 
as  $10,  with  a  maximum  cost  in  winter  of  $24  and  a  minimum  in 
summer  of  $6.25;  this  tower  as  well  as  the  single-circuit  structure 


Section  A-B 


Section  E-F 


FIG.  60. — Double  circuit  tower  used  by  the  Ontario  Hydro-Electric 
Power  Commission. 

previously  mentioned,  is  designed  for  a  clearance  to  ground  of  the 
lowest  suspension,  of  45  ft.,  with  an  overall  height  of  about  64 
ft.  6  in.;  the  base  spread  of  the  double-circuit  structure  is  17  ft, 
and  that  of  the  single-circuit,  16  ft.;  an  outline  of  the  design  of  the 


STEEL  TOWER  CONSTRUCTION 


123 


double-circuit  structure  and  a  view  of  the  same  in  the  line,  are 
shown  in  Figs.  60  and  61,  respectively. 

The  contractor's  cost  for  the  assembling  of  towers  for  a  4.2-mile 
stretch  of  45-ft.  double-circuit  construction  built  in  the  West 
under  high-priced  labor  conditions,  is  given  as  $19.70  per  tower; 
unskilled  labor  received  28  cents  and  linemen  and  mechanics 
45  cents  per  hour;  the  labor  conditions  prevailing  did  not  allow 


•• 


FIG.  61. — Double  circuit  tower  shown  in  Fig.  60. 

the  use  of  common  labor  to  replace  mechanics,  where  feasible,  as 
would  be  the  case  in  the  Middle  West. 

The  raising  or  erection  of  towers  is  ordinarily,  comparatively 
simple,  dependent  in  cost  and  progress  upon  the  skill  and  inge- 
nuity of  the  foreman  in  charge,  and  his  aptitude  for  "  rigging." 

Several  different  methods  of  raising  towers  have  been  employed 
by  different  construction  men,  such  as  using  a  tall  gin  pole  with 


124  TRANSMISSION  LINE  CONSTRUCTION 

blocks  at  the  top,  a  two-gin-pole  arrangement,  shear  legs,  and  a 
variation  from  straight  shear  legs,  where  an  A-frame  or  a  shear 
pole  with  a  6-in.  or  8-in.  sheave  at  the  top  was  used. 

High  gin  poles  with  the  raising  blocks  attached  at  the  top,  and 
the  fall-line  reeved  through  a  snatch  block  at  the  butt,  have 
been  used  in  the  construction  of  many  important  lines,  as  have 
tall  A-frames  similarly  rigged;  arrangements  of  this  kind,  how- 
ever, are  heavy  to  place  in  position  for  work  and  to  transport, 
though  by  the  use  of  trucks  permanently  attached  to  A-frames, 
they  may  be  made  quite  convenient  in  this  latter  respect.  A  typ- 
ical view  of  a  tower  being  raised  by  means  of  a  high  gin  pole  is 
shown  in  Fig.  62;  where  such  a  pole  is  used  as  shown,  it  must  be 
set  outside  of  the  line  of  the  anchors,  it  requires  considerable 


FIG.  62. — Raising  tower  with  tall  gin  pole. 

time  to  erect  and  guy,  and  must  be  quite  carefully  handled  in 
lowering  after  the  tower  is  raised.-  This  method  of  raising  is 
being  supplanted  by  the  shear-pole  rig. 

An  arrangement  using  two  gin  poles,  one  on  each  side  of  the 
tower  and  practically  lifting  it,  is  shown  in  Figs.  63  and  64; 
this  method  involves  the  use  of  two  fairly  tall  gins  with  their 
guying  and  attachment  of  the  blocks  to  the  structure,  and  their 
two  fall  lines;  while  it  may  work  out  very  well  for  certain  types 
of  structures,  it  is  not  to  be  preferred  over  that  of  using  one  gin 
pole,  and  certainly  not  over  that  of  employing  a  shear  rig. 

For  all-around  purposes,  the  writer  believes  that  shear  legs, 
or  a  shear  or  gin  pole  provided  with  a  sheave  at  the  top,  provide 
the  best  rig  for  raising  towers;  where  the  straight  shear  method 


STEEL  TOWER  CONSTRUCTION 


125 


is  used,  the  shear  legs  are  inclined  ahead  at  such  an  angle  that, 
traveling  backward  as  the  raising  cable  is  pulled  up,  it  will  take 
the  thrust  until  the  tower  top  has  risen  far  enough  to  bring  the 
raising  pull  in  a  straight  line  from  the  tower  to  the  stakes  to  which 
the  blocks  are  attached;  where  a  sheave  instead  of  a  groove 
is  provided  at  the  top  of  the  frame  or  pole,  the  pole  is  inclined 
slightly  ahead  of  the  vertical  and  maintained  there  until  the 
raising  line  is  just  clearing,  by  means  of  a  pair  of  light  blocks 
hooked  into  the  tower  structure  at  some  convenient  point.  In 
Fig.  65  is  shown  a  type  of  shear  legs  recommended  by  one  of 
the  tower  manufacturing  companies  for  raising  towers  up  to 
3000  Ib.  in  weight  and  about  80  ft.  in  overall  height,  and  in 


FIG.  63. 

Raising  towei 


FIG.  64. 
-two  gin  pole  method. 


Fig.  66  is  illustrated  a  shear  pole  as  often  used,  provided  with  a 
6-in.  or  8-in.  sheave  at  the  top;  in  lieu  of  this  latter,  the  writer 
has  often  used  an  ordinary  6-in.  top,  30-ft.  cedar  pole  with  a 
6-in.  snatch-block  hooked  in  a  guy-strand  sling  at  the  top,  with 
a  through  bolt  at  the  top  to  prevent  slipping;  in  using  this  impro- 
vised rig  care  must  be  taken  to  see  that  the  pole  does  not  turn 
or  twist  so  as  to  foul  the  sling  and  prevent  it  from  pulling  off 
clear,  when  the  raising  line  ceases  to  bear. 

An  A-frame  made  up  of  3-in.  pipe  suitably  braced  and  pro- 
vided with  a  sheave  at  the  top,  and  arranged  so  that  its  width 


126 


TRANSMISSION  LINE  CONSTRUCTION 


at  the  base  was  the  same  as  that  of  the  tower,  has  been  used 
with  very  satisfactory  results  by  bolting  the  frame  to  the  bottom 
main  members  of  the  tower  and  leaving  the  lower  ends  of  the 
A-frame  to  project  and  by  the  thrust  of  the  cable  in  raising, 
dig  into  the  ground  and  take  care  of  the  horizontal  thrust  of 
the  structure  as  it  is  being  erected;  the  objection  to  any  kind 
of  an  A-frame,  however,  is  that  it  cannot  be  handled  as  eas- 
ily or  as  roughly  from  place  to  place,  as  a  simple  pole  can. 
The  height  of  any  kind  of  shear  fixture  need  not  be  more  than 


Plate. 


W.I.  Pipe 
Separators. 


FIG.  65. — A-frame  for  raising  towers. 


30  ft.  to  35  ft.  for  towers  up  to  70  ft.  or  80  ft.  in  overall  length, 
and  a  6-in.  top  cedar  pole  will  handle  all  ordinary  work.  To 
prevent  the  butt  of  the  fixture  or  pole  from  slipping,  it  may 
be  shod  with  a  6-in.  or  8-in.  spike,  it  may  have  the  lower  end 
sharpened,  or  as  has  worked  out  very  well  in  the  case  of  a 
single  pole,  it  may  be  set  into  a  shallow  hole,  8  in.  or  10  in.  deep. 
To  take  up  the  horizontal  thrust  in  raising,  the  bottom  of  the 
tower  must  be  secured  in  some  way,  which  in  addition  to  per- 


STEEL  TOWER  CONSTRUCTION 


127 


forming  that  function  also  facilitates  its  rotation  about  the  ends 
of  the  bottom  legs  as  its  comes  up;  this  is  usually  done  by  the 
use  of  some  form  of  trunnion,  varying  from  an  elaborate  set,  in 
which  each  leg  is  bolted  to  a  separate  roller  provided  with  two 
bearing  blocks  each,  equipped  with  stake  chains  for  anchoring, 
.to  a  field-made  device  consisting  of  a  " borrowed"  section  of 
cedar  pole,  about  6  in.  or  8  in.  in  minimum  diameter  and  about 
4  ft.  or  so  longer  than  the  width  of  the  base  of  the  tower,  to  which 


.8"Sheave. 
•tf  Plate. 


FIG.  66. — Shear  pole  for  raising  towers. 

the  ends  of  the  main  members  are  bolted ;  in  the  case  of  the  sec- 
tion of  old  pole,  the  ground  provided  the  bearing  and  the  stake 
chains  were  pieces  of  rope,  snubbed  back  to  stakes. 

Either  a  long  6-in.  or  8-in.  diameter  roller,  similar  to  the  im- 
provised rig  just  described,  provided  with  bands  (inside  of  which 
the  roller  can  turn  easily)  to  which  stake  chains  are  attached 
to  hold  the  trunnion  against  the  raising  thrust,  such  as  is  shown 
in  Fig.  67,  or  the  two-roller  method  with  bearing  blocks  as 
described  will  give  satisfactory  results;  the  use  of  the  pipe 


128  TRANSMISSION  LINE  CONSTRUCTION 


<»>?'     Stake  Rings  about 
^"Inside  Diameter 


FIG.  67. — Raising  trunnion. 


FIG.  68. — Raising  struts — used  to  reinforce  tower  against  strain  of  erection. 


STEEL  TOWER  CONSTRUCTION 


129 


A-frame,  doing  away  with  any  special  arrangement,  is  also  satis- 
factory in  solid  ground;  the  writer's  personal  experience  causes 
him  to  favor  the  long  single-roller  method,  except  probably  in 
the  case  of  heavy  towers. 

In  the  raising  of  many  types  of  towers,  they  must  be  braced 
at  the  bottom  in  order  to  withstand  the  strains  produced  in 
the  erection;  this  is  usually  specified  in  the  manufacturer's 
proposals;  ordinarily  3 -in.  X3-in.  or  4-in.  X4-in.  stuff  will  be 
ample  and  in  the  course  of  most  jobs,  the  bottom  bracing  is 
secured  as  needed  along  the  right-of-way.  Fig.  68  shows  the 
application  of  this  reinforcement. 


FIG.  69. — Raising  tower  with  shear  pole. 

Figure  69  shows  the  raising  of  a  tower  with  a  sheaf  pole 
provided  with  a  sheave  at  the  top;  in  this  case  it  will  be 
noted  that  a  fairly  high  pole  is  used,  and  that  it  is  set  outside 
of  the  line  of  anchors  and  is  not  dropped  when  the  tower-raising 
line  clears. 

Figures  70,  71.  72.  73  and  74  show  the  steps  in  raising  a  tower 
with  the  shear  pole  set  at  about  the  center  of  the  space  enclosed 
by  the  anchors  and  the  series  is  self-explanatory;  it  will  be 
noted  that  'the  work  is  being  done  with  the  improvised  rig 
described  earlier  in  the  chapter. 

In  general,  for  the  raising  of  a  structure  by  almost  any  method, 
the  actual  time  required  for  the  erection  itself  is  only  a  small 
part  of  the  average  time  consumed,  and  so  the  efficiency  of  the 


130 


TRANSMISSION  LINE  CONSTRUCTION 


methods,  when  compared  with  each  other,  will  depend  in  each 
case  upon  the  ease  and  rapidity  with  which  the  rigging  can  be 
taken  down,  transported  to  the  next  tower  location,  and  set  up 
again. 


FIG.  70. 


FIG.  71 


FIG.  72.  FIG.  73. 

Raising  tower  with  short  shear  pole. 

Where  a  shear-pole  method  of  raising  is  used,  the  general 
routine  of  raising  a  tower  will  require  a  crew  consisting  of  a 
foreman,  six  men,  and  a  team  and  teamster;  and  equipment 
and  rigging  of  one  G-in.  top,  30-ft.  to  35-ft.  pole  with  a  6-in. 


STEEL  TOWER  CONSTRUCTION  131 

or  8-in.  sheave  mounted  at  the  top,  one  long  roller-trunnion, 
about  6  in.  or  8  in.  in  diameter  and  of  the  length  called  for,  two 
4-in.  X4-in.  raising  struts  as  may  be  required  for  the  particular 
tower,  one  3/4-in.  flexible  plough-steel  raising  cable  about 
200  ft.  to  250  ft.  long,  provided  with  a  half  dozen  or  so  Crosby 
clamps,  one  team  chain,  two  special  stake  chains  (chains  made 
up  with  rings  about  4  1/2  in.  or  5  in.  inside  diameter,  to  receive 
stakes  about  3  1/2  in.  to  4  in.  in  diameter,  spaced  2  ft.  or  3  ft. 
apart  throughout  their  length),  a  set  of  three-sheave  8.-in.  blocks 


FIG.  74. — Raising  tower  with  short  shear  pole. 

reeved  with  3/4-in.  or  7/8-in.  rope  to  extend  75  ft.  or  80  ft., 
one  pair  double-sheave  6-in.  blocks  with  5/8-in.  line  to  extend 
about  50  ft.,  one  pair  4-in.  double-sheave  blocks  with  5/8-in. 
line  to  extend  about  50  ft.,  three  50-ft.  3/4-in.  lines  for  guying 
shear  pole,  two  3/4-in.  lines  about  100  ft.  long  for  tower  side 
guys  where  they  may  be  needed,  twenty  or  twenty-five  4-ft. 
stakes  about  4  in.  in  diameter,  and  a  few  post-mauls,  shovels, 
wrenches  and  axes.  The  rigging  will  be  loaded  into  a  wagon 


132          TRANSMISSION  LINE  CONSTRUCTION 

with  the  gin  pole  dragging  behind  in  moving  from  tower  to 
tower,  as  also  may  the  raising  cable  if  desired,  or  the  whole 
outfit  can  be  carried;  if  they  are  snaked  along,  the  time  of  coil- 
ing and  uncoiling  the  cable  will  be  saved. 

Upon  arriving  at  the  tower  to  be  raised,  one  man  will  scoop 
out  a  shallow  hole  for  the  butt  of  the  gin  pole  if  it  is  not  shod, 
four  of  the  men  will  carry  the  gin  pole  into  position,  lay  out  the 
guys  and  4-in.  blocks  and  drive  guy  stakes,  etc.,  while  the  other 
man  and  the  teamster  will  unload  the  rigging  from  the  wagon. 
Then  two  men  will  set  the  tower  back-guy  stakes,  two  men  the 
pulling  stakes,  and  the  other  two  will  carry  the  raising  line  up 
in  place  and  fasten  it  to  the  tower  at  about  the  lower  cross-arm 
by  means  of  the  team-chain  used  as  a  sling;  this  done,  the  6-in. 
back-line  blocks  will  be  laid  out  and  hooked  on  and  the  8-in. 
raising  blocks  extended;  then  the  raising  cable  will  be  placed  in 
the  sheave  of  the  shear  pole,  and  the  pole  raised  into  place  by 
means  of  the  4-in.  blocks  pulling  from  a  sling  fastened  to  one  of 
the  bottom  members  of  the  upper  face  of  the  tower,  the  men 
helping  in  this  by  lifting  at  the  start;  if  raising  struts  are  required 
they  should  preferably  be  placed  before  the  pole  is  raised.  The 
shear-pole  guys  are  then  snubbed  to  their  stakes,  and  the  trun- 
nion or  roller  placed  in  position,  bolted  in  place,  blocked  level 
where  necessary,  or  all  around  where  the  ground  is  soft,  and  the 
thrust  stakes  driven;  if  the  tower  is  lying  a  little  at  an  angle  to 
the  line,  enough  slack  may  be  left  in  one  of  the  trunnion  chains 
as  may  be  necessary  to  correct  this  by  letting  the  tower  swing 
into  its  proper  position  as  the  strain  comes  on,  but  care  should  be 
taken  that  none  of  the  stakes  will  interfere  with  the  cross-bracing 
of  the  tower  as  it  comes  ahead,  or  for  that  matter,  that  the  bracing- 
will  not  foul  the  tops  of  the  stakes  as  the  tower  raises  up. 

With  the  placing  of  the  trunnion  everything  is  ready  for  the 
erection,  and  the  raising  blocks  are  hooked  into  the  cable  with 
the  fall  line  pulling  away  from  the  tower;  to  prevent  the  blocks 
from  twisting,  a  weight  of  some  kind,  such  as  a  post-maul,  is 
fastened  to  the  head  raising  block;  the  team  is. hooked  to  the  fall 
line  and  one  man  stays  with  the  teamster,  one  goes  to  the  tower 
back  guy,  one  to  the  shear-pole  blocks  to  keep  the  pole  in  posi- 
tion until  the  cable  clears  it,  one  watches  the  trunnion,  and  the 
other  two  watch  side  guys  and  stand  ready  with  drift  pins, 
wrenches  and  bolts. 

As  the  team  starts,  the  tower  takes  the  slack  out  of  the  trun- 


STEEL  TOWER  CONSTRUCTION  133 

nion  chain  and  comes  up  nicely — usually — the  team  going 
slowly  and  evenly;  as  the  line  clears  the  shear  pole,  this  is  dropped 
back  and  the  men  with  tools  watch  as  the  tower  is  slowly  pulled 
into  a  vertical  position  and  signal  for  the  team  to  stop  as  the 
ends  of  the  corner  posts  come  within  a  short  distance  of  the 
tops  of  the  anchors,  and  with  the  team  holding  their  slack,  the 
tower  is  worked  into  position  by  the  man  at  the  back  guy,  with 
such  shifting  of  the  trunnion,  which  may  have  to  be  loosened,  as 
may  be  required;  as  the  ends  of  the  corner  posts  slip  over  the 
anchors,  they  are  caught  in  position  with  a  drift  pin  and  bolts 
loosely  inserted;  with  the  forward  legs  fastened,  the  tower  is 
pulled  over  a  little  so  as  to  remove  the  strain  from  the  trunnions, 
the  back  guy  following  up,  and  the  trunnion  is  removed,  the 
tower  let  back  and  the  legs  bolted  in  place;  the  bolts  are  then 
set  up  all  around  and  the  erection  is  completed. 

The  erection  of  a  flexible  structure  is  carried  out  along  the 
same  lines,  with  the  exception  that  in  most  cases  the  design  is  such 
that  no  trunnion  is  required,  the  ends  of  the  main  members  being 
connected  with  one  bolt  on  each  side  and  serving  the  purpose; 
the  raising  of  one  of  the  riveted  type  of  flexible  towers  with  heavy 
channel  ma'n  members,  it  is  apparent,  therefore,  is  very  easy, 
and  as  the  same  methods  apply  in  either  case  no  special  mention 
need  be  made  of  the  same. 

The  number  of  towers  that  can  be  raised  a  day  by  a  crew  such 
as  described  above,  will  vary  with  the  design  of  the  tower,  its 
weight,  the  weather,  the  location,  the  condition  of  the  ground, 
the  crew  itself  and  the  "luck"  they  have. 

On  a  job  in  the  Middle  West,  with  a  crew  as  above  outlined,  the 
cost  of  raising  50-ft.  single-circuit  towers  weighing  about  1900 
Ib.  each,  averaged  about  $3  per  tower,  with  the  crew  raising  about 
eight  towers  daily;  the  work  was  carried  on  in  the  late  fall  and 
early  winter  and  the  men  were  quartered  in  camps;  shear  poles 
and  A-frames,  with  sheave  at  the  top,  were  used  for  erecting. 
On  another  job,  as  noted  in  the  Electrical  World  for  Sept.  9, 
1911,  the  cost  of  erecting  45-ft.  single-circuit  towers  of  medium 
weight  was  $6.10  each,  using  twelve  men  with  gin-pole  rigging; 
a  maximum  of  fourteen  towers  was  erected  in  one  day;  it  will  be 
noted  that  this  line  is  only  about  8.5  miles  long.  In  the  line 
work  in  connection  with  the  Roosevelt  Dam  Reclamation  pro- 
ject, where  light  35-ft.  to  40-ft.  double-circuit  towers  were  used, 


134  TRANSMISSION  LINE  CONSTRUCTION 

a  crew  of  six  men  would  average  about  ten  towers  erected  each 
day;  no  wage  scale  is  given. 

The  cost  of  erecting  the  single-circuit  towers  of  the  Ontario 
Hydro-Electric  Power  Commission  system,  45-ft.  standard  and 
weighing  3200  Ib.  averaged  $3.50  each,  the  work  being  done  in 
the  summer  and  early  fall;  the  raising  cost  of  the  45-ft.  3995-lb. 
double-circuit  towers  on  the  same  system  was  $4.75  each,  with  a 
minimum  of  $2.45.  During  the  summer  time  the  crew  of  five 
or  six  men,  foreman,  and  team,  could,  with  "good  going,"  raise 
eight  towers  every  day.  It  may  be  noted  that  on  this  work  gin 
poles,  A-frames  and  shear  legs  were  all  used,  the  most  satis- 
factory results  being  obtained  with  the  latter. 

On  the  4.2-mile  line  built  in  the  West,  with  the  high-priced 
labor  conditions,  the  cost  of  erecting  4400-lb.,  45-ft.  towers  by  the 
two-gin-pole  method  shown  in  Fig.  63,  is  given  as  $9.80  per 
tower. 

The  labor  costs  on  steel  construction  have  in  general  been 
higher  than  would  appear  necessary,  this  being  due,  in  many  cases 
at  least,  to  the  fact  that  the  work  being  line  construction,  it  has 
been  assumed  that  linemen  must  be  employed,  regardless  of 
whether  or  not  the  same  work  could  be  done  as  well  by  ordinary 
labor;  of  course  there  are  places  where  common  labor  will  not 
do  and  likewise  localities  where  labor  organizations  call  for  cer- 
tain classes  of  mechanics  for  certain  parts  of  the  work,  and  a 
skilled-labor  price  may  have  to  be  paid  for  unskilled-labor 
work. 

The  influence  of  this  feature  on  the  cost  of  steel  construction  is 
conclusively  proven  in  the  case  of  two  similar  lines  of  about  the 
same  length,  one  of  cedar  pole  and  the  other  of  steel  tower  con- 
struction, built  by  the  same  operating  company  under  about  the 
same  conditions,  where  the  steel  tower  line  was  built  at  a  sub- 
stantially lower  first  cost  than  that  of  the  wood,  as  noted  in 
Chapter  XII.  The  company  cites  as  the  reason  for  the  differ- 
ence the  fact  that  the  tower  line  work,  wire  stringing  and  all,  was 
done  with  common  labor. 

With  systematic  plans  for  carrying  on  the  work  and  with 
judicious  selection  of  labor  and  equipment,  there  is  no  reason  why 
the  present  average  labor  cost  of  steel  tower  construction  can- 
not be  reduced. 


CHAPTER  VII 


,2x4" 


x  4  •      Section  at  Top 


REINFORCED  CONCRETE  CONSTRUCTION 

Reinforced  concrete  poles  are  divided  into  two  general  classes, 
the  solid  and  the  hollow  types;  the  latter  include  such  as  are 
built  with  the  major  portion  hollow  and  the  rest  solid. 

The  solid  type  is  the  one 
that  has  been  used  in  a  great 
deal  of  the  construction  of 
this  character  in  the  United 
States,  probably  the  main 
reason  being  that  isolated 
companies  have  all  built  their 
own  poles,  and  the  work 
being  to  a  great  extent  a 
preliminary  investigation  as 
to  the  possibilities  of  concrete 
in  line  construction,  have  not 
cared  to  go  to  any  great  ex- 
pense for  forms  or  appliances, 
such  as  would  be  required 
for  molding  hollow  poles. 
In  the  casting  of  solid]  poles 
most  companies  have  em- 
ployed horizontal  forms, 
though  there  have  been 
several  instances  of  poles  of 
great  size  where  it  was 
deemed  expedient  on  account 
of  their  weight,  to  build  ver- 
tical forms  at  the  pole  loca- 
tions and  cast  them  in  place, 
so  that  upon  the  removal  of 


FIG. 


Bolts 

Detail  of  Splice 

75. — Forms — Marseilles  Land  and 
Water  Co.'s  concrete  pole. 


the  forms  the  poles  would  be 

ready  for  service,  after  seasoning  a  reasonable  length  of  time. 

The  forms  for  poles  consist  of  tapered  troughs  of  usually  square 
or  hexagonal  section,   made  of  wood  throughout,   or  of  wood 

135 


136 


TRANSMISSION  LINE  CONSTRUCTION 


sheathed  with  galvanized  iron,  so  constructed  that  the  sides  can 
be  readily. removed  after  the  concrete  has  set  for  a  day  or  so; 
where  poles  of  square  section  are  used,  they  are  generally  made 
with  the  corners  rounded  off  or  beveled,  not  only  adding  to  the 
appearance  of  the  poles,  but  making  them  easier  to  handle. 
The  general  requirements  of  a  form  for  pole  work  are  the  same 
as  for  any  kind  of  concrete  work  where  the  forms  are  to  be  used 
over  and  over  again;  the  material  should  be  such  that  there  will 
be  no  warping,  and  the  construction  should  be  such  that  there  will 


FIG.  76. — Forms  used  for  Oklahoma  Gas  &  Electric  Co.'s 
hollow  concrete  poles. 

be  no  leakage  in  using  sloppy  concrete,  no  distortion  or  bulg- 
ing of  the  sides  when  filled,  and  that  it  be  sufficiently  rigid  to 
retain  its  shape  with  ordinary  handling.  A  sheet-metal  form 
properly  braced,  probably  combines  these  qualities  to  the  great- 
est extent  and  should  be  superior  to  wood,  though  cypress  has 
been  used  with  very  satisfactory  results. 

The  steel  for  reinforcement  has  in  most  cases  been  some  type 
of  bar  with  a  mechanical  bond  and  in  many  cases  has  been  pro- 
vided with  a  spiral  wrapping  of  wire  similar  to  a  Considere  col- 
umn, or  with  bands  fastened  to  the  longitudinal  rods;  it  appears, 
however,  that  the  use  of  this  spiral  or  band  reinforcement  in 


REINFORCED  CONCRETE  CONSTRUCTION       137 

many  cases  is  due  more  to  the  necessity  for  a  means  of  tying  the 
steel  together  for  handling,  than  it  is  to  a  knowledge  of  the 
increased  strength  resultant  upon  its  employment. 

As  an  example  of  what  is  probably  the  largest  installation  of 
solid  concrete  poles  for  purely  transmission  purposes  in  the  United 
States  to-day,  a  description  of  the  pole  used  by  the  Marseilles 
Land  &  Water  Company  of  Marseilles,  111.,  will  be  of  interest; 
the  total  length  of  this  concrete  pole  line  is  about  30  miles.  The 
standard  pole  length  is  30  ft.  with  a  6-in.  square  top  and  a  9-in. 
butt;  the  reinforcement,  as  shown  in  section  at  ground  in  Fig.  77, 
consists  of  six  1/2-in.  square  high  carbon  rods  located  11/2  in. 
from  the  face  of  the  pole  and  running  the  length  of  the  pole,  with 
two  1/2-in.  rods  similarly  located,  extending  only  7  ft.  up  from 
the  butt;  as  described  in  the  Engineering  Record  for  May  21, 


x  7  ft. 


".v.-.-  ^V7V  ••«•••< 
^;<V.A:K.:Si-C 

^A'.'^'.'A- 


^K^T^g^W? 
^^^^^f^v^^^  - 

\!>-^%'-^>>-*X-?.^if.^-'-'i^';-'.'^--'c>>'Bfc4  — ~" 


FIG.  77. 


I 

FIG.  78. 


x  29  6 


x  296 


l/2  x  18  0 


1910,  the  full  length  steel^is  distributed  so  as  to  take  care  of 
the  heaviest  strain  in  the  direction  of  the  line  instead  of  trans- 
verse to  it.  The  poles  are  designed  for  two  three-phase  circuits 
of  No.  4  B.  &  S.  copper  carried  in  125-ft.  spans. 

The  poles  were  molded  in  wooden  forms,  sectional  views  of 
which  are  shown  in  Fig.  75,  a  mixture  consisting  of  1  part  cement 
to  5  parts  gravel  being  used;  the  gravel  graded  from  fine  sand 
up  to  stones  from  1/2  in.  to  3/4  in.  in  diameter.  The  sides  of 
the  forms  were  removed  in  twenty-four  hours  and  then  after 
curing  for  two  days  longer,  the  pole  was  turned  on  its  side 
and  the  bottom  removed,  after  which'  the  pole  was  allowed 
to  season  from  two  to  three  weeks  or  longer  before  being  con- 


138  TRANSMISSION  LINE  CONSTRUCTION 

sidered  ready  to  set.  This  design  of  pole  in  the  30-ft.  length 
weighed  about  1700  Ib. 

The  Welland  Canal  concrete  pole  line  is  probably  one  of  the 
next  largest  of  this  type  of  construction  used  for  transmission 
purposes,  not  including  poles  used  in  city  distribution  work, 
being  about  12  miles  long  with  35-ft.  poles  as  standard.  As 
described  in  the  Electrical  World  for  Nov.  3,  1906,  this  line  is 
designed  to  carry  two  three-phase  circuits  in  220-ft.  spans,  the 
poles  being  figured  for  a  horizontal  pull  at  the  top  of  2000  Ib.; 
with  the  35-ft.  length  as  standard,  the  pole  heights  vary  from 
that  up  to  75  ft. 

Quite  extensive  use  of  solid  concrete  poles  has  also  been  made 
for  electric  railway  work,  by  the  Fort  Wayne  &  Wabash  Valley 
Traction  Company,  the  Syracuse  Rapid  Transit  Company,  and 
the  Cleveland  Railway  Company.  The  poles  for  this  class  of 
work  have  been  about  30  ft.  in  length  and  of  square  section,  and 
in  the  case  of  the  first-mentioned  company,  eight  1/2-in.  square 
twisted  bars  were  used  the  full  length  of  the  pole,  a  bar  being 
placed  at  each  corner  and  at  the  middle  of  each  face,  the  steel 
being  located  1  in.  in  from  the  face  of  the  pole;  no  hooping  or 
transverse  reinforcement  of  any  kind  was  used.  In  molding  these 
poles  the  method  of  procedure  was  as  follows:  About  1  in.  of 
concrete  was  placed  over  the  entire  bottom  of  the  form,  on  which 
were  laid  the  three  bars  for  the  lower  face,  then  the  form  was 
poured  half  full  and  the  two  bars  for  the  middle  of  the  side 
faces  placed,  after  which  the  concrete  was  filled  in  to  within  1  in. 
of  the  top,  the  three  bars  for  the  top  face  placed,  and  the  concrete 
poured  in  to  complete  the  pole  and  trowelled  smooth.  In  the 
casting  of  this  pole  no  tamping  at  all  was  done,  reliance  being 
placed  upon  trowelling  and  spading  to  secure  a  homogeneous 
structure;  it  is  apparent  that  it  would  not  be  feasible  to  subject 
a  structure  of  this  kind  with  loosely  placed  bars  to  indiscrimina- 
tive  tamping,  and  it  is  questionable  if  very  uniform  results  can  be 
obtained  without  having  the  steel  held  in  place  or  fabricated  in 
some  way,  so  that  this  may  be  done. 

Both  the  Syracuse  Rapid  Transit  Company  and  the  Cleveland 
Railway  Company  have  also  constructed  their  poles  along  simi- 
lar lines  without  fabricated  reinforcement,  and  details  of  the 
Syracuse  pole  as  described  in  the  Engineering  Record  for  Oct. 
1,  1910,  are  given  below. 

This  pole  is  made  with  6-in.  top  and  11-in.  butt,  is  f30  t.  long 


REINFORCED  CONCRETE  CONSTRUCTION       139 

and  square  in  section,  with  a  2-in.  bevel  on  corners  above  the 
ground  line;  it  is  more  heavily  reinforced  than  the  Fort  Wayne 
pole  just  described.  In  each  corner,  as  shown  in  Fig.  78,  a 
5/8-in.  twisted  bar  was  used,  running  the  full  length  of  the  pole, 
with  a  similar  full-length  1/2-in.  bar  in  the  middle  of  each  face, 
then  in  each  face  midway  between  the  two  full-length  bars  was 
placed  an  18-ft.  1/2-in.  bar,  as  extra  reinforcement  for  the  lower 
portion  of  the  pole.  The  steel  was  all  laid  in  as  in  the  case  of 
the  Fort  Wayne  pole  and  the  concrete  was  proportioned  as  fol- 
lows: 1  cement,  2  sand,  and  2  crushed  stone,  a  mix  that  is  quite 
a  bit  richer  than  is  ordinarily  used  in  pole  work. 


FIG.  79. — Forms  and  reinforcing  steel — Pennsylvania  R.  R.  concrete  poles. 

Probably  the  heaviest  solid  concrete  pole  line  in  commercial 
use  for  the  support  of  wires  of  any  kind,  is  the  telegraph  and 
telephone  lead  of  the  Pennsylvania  Railroad  built  across  a 
5-mile  stretch  of  swamp  land  on  the  Meadows  Division  between 
Newark  and  Bergen  Hill  to  carry  ultimately  sixty  open  wires 
and  two  forty-pair  cables  in  average  spans  of  120  ft.,  described 
in  the  Electrical  World  for  Sept.  2,  1911.  The  design  which  was 
made  by  R.  D.  Coombs,  is  based  upon  a  maximum  load  of  6000 
Ib.  applied  at  a  point  6.5  ft.  below  the  top.  The  poles  are  of 
square  section  with  chamfered  corners  and  the  steel  is  fabri- 
cated, mechanical  bond  bars  tied  together  with  horizontal  bands, 
being  used,  as  will  be  noted  in  Fig.  79.  The  mix  was  1:2:4, 


140 


TRANSMISSION  LINE  CONSTRUCTION 


REINFORCED  CONCRETE  CONSTRUCTION       141 


well  tamped  and  the  steel  was  located  1  in.  in  from  the  face  of 
the  pole;  the  overall  lengths  of  the  poles  varied  from  35  ft. 
to  65  ft. 

While  the  solid  design  of  pole  has  been  used  in  the  greater 
number  of  installations  in  this  country,  the  commercial  develop- 
ment of  the  hollow  type  has  been  given  the  most  attention  in 
Europe,  and  in  this  country  there  is  one  very  notable  exception 
to  the  general  rule. 

In  Europe  the  commercial  manufacture  of  poles  of  hollow 
design  is  practised  on  quite  an  extensive  scale,  two  machine 
processes  being  used,  one  of  which  applies  the  concrete  quite 


FIG.  81. 

wet  and  the  other  comparatively  dry.  The  first  method  is  the 
centrifugal  process  of  Otto  &  Schlosser  of  Eisen,  Saxony,  in 
Germany,  and  is  described  in  detail  in  the  Cement  Age  for  March, 
1911. 

The  process  consists  iii  placing  in  a  tubular  form  of  the  desired 
dimensions,  fabricated  reinforcement  consisting  of  various  num- 
bers of  longitudinal  bars  held  in  place  by  an  inner  and  an  outer 
spiral  of  wire,  as  is  well  shown  in  Figs.  80  and  81,  then  filling  the 
mold  with  as  much  wet  concrete  as  may  be  required  to  give  the 
desired  wall  thickness,  and  then  revolving  this  shell  or  form  at 
a  high  speed  in  a  lathe-like  machine,  the  centrifugal  action 
packing  the  concrete  in  a  homogeneous  layer  on  the  inside  walls 
of  the  form. 

Going  a  little  more  into  detail,  the  forms  are  built  up  of  Ion- 


142  TRANSMISSION  LINE  CONSTRUCTION 

gitudinal  strips  or  staves  of  wood,  lined  with  sheet  iron;  giving 
the  pole  a  smooth  exterior  finish,  and  they  are  split  in  halves 
longitudinally.  The  reinforcing  steel  is  held  rigidly  in  position 
by  means  of  small  concrete  spacing  blocks  wired  to  the  fabricated 
unit  at  different  points.  In  a  typical  pole  29.5  ft.  long,  5.9  in. 


FIG.  82. — Machine  used  in  molding  centrifugal  type  concrete  poles. 

in  diameter  at  the  top  and  9.5  in.  at  the  butt,  sixteen  1/4-in. 
rods  29.5  ft.  long  and  fifteen  1/4-in.  rods  about  19.7  ft.  long  were 
used  for  longitudinal  reinforcement,  with  an  outer  and  inner 
spiral  of  No.  11  wire  with  a  screw  pitch  of  6  in.  to  8  in.,  tying 
the  same  together. 

In  the  manufacture  of  this  pole,  the  concrete  tends  to  separate 


REINFORCED  CONCRETE  CONSTRUCTION       143 

• 

into  layers  of  its  individual  components  upon  subjection  to 
centrifugal  action,  owing  to  their  different  specific  gravities, 
and  it  is  found  necessary  to  introduce  a  binding  material  to  coun- 
teract this;  disintegrated  asbestos  fiber  is  used  for  this  purpose, 
and  tends  to  mat  the  concrete  and  to  prevent  the  sand  from 
being  forced  to  the  outside;  the  addition  of  the  asbestos  does 
not  seem  to  depreciate  the  strength  of  the  concrete;  the  mix- 
ture used  for  these  poles  appears  to  be  about  1  part  cement 
to  6  or  7  parts  sand,  no  information  being  given  as  to  the  per- 
centage of  asbestos  fiber  used. 

The  lathe  or  machine  developed  for  the  manufacture  of  these 
poles  is  shown  in  Fig.  82.  It  consists  of  a  series  of  units,  similar 
to  the  one  in  the  foreground  of  the  illustration,  provided  with 
suitable  clamps  and  adjustable  rollers;  in  between  the  rollers 
are  self-centering  screw  clamps  similar  to  those  used  on  a  lathe, 


-a 


FIG.  83. 

and  these  serve  as  pulleys  for  the  belting;  a  line  shaft,  driven 
by  electric  motor,  runs  the  length  of  the  installation  of  machines 
and  the  units  are  belted  directly  to  this.  The  speed  varies 
from  500  r.p.m.  to  1000  r.p.m.,  depending  upon  circumstances. 
Varying  with  the  thickness  of  the  walls  of  the  pole,  the  length 
of  time  required  for  the  proper  formation  and  compacting  of 
the  concrete  in  the  forms,  runs  from  ten  to  fifteen  minutes. 

By  inclining  the  axis  of  the  form  as  in  Fig.  83,  the  thickness 
of  the  walls  of  the  pole  may  be  vaiied  from  top  to  bottom  as 
desired;  for  a  straight  cylindrical  pole,  the  horizontal  position 
of  the  form  will  give  walls  of  uniform  thickness,  but  for  a  pole 
tapering  in  diameter,  the  small  end  will  have  to  be  lowered  to 
secure  the  same  result;  the  amount  of  inclination  required 
depends  upon  the  speed  of  the  form  and  the  amount  of  its  taper, 
and  must  be  determined  by  experiment. 

Upon  completion  of  the  formation  of  the  pole,  the  machine 
is  stopped  and  a  train  of  rollers  such  as  that  shown  at  the  end  of 
the  unit  in  the  foreground  of  Fig.  82,  is  raised  into  bearing  with 


144 


TRANSMISSION  LINE  CONSTRUCTION 


the  form  and  it  is  withdrawn;  the  pole  is  allowed  to  remain  in 
the  form  for  ten  to  twelve  hours  after  which  it  is  removed  and 
seasoned  in  damp  sand  until  thoroughly  hardened.  In  Fig.  84 
is  shown  a  view  of  the  factory  with  poles  skidded  in  the  fore- 
ground much  like  a  stock  of  wooden  poles,  and  in  Fig.  85  an 
installation  of  this  type  of  poles  in  a  German  city,  is  illustrated. 
The  other  machine  process  developed  in  Europe  is  the  Sieg- 
wart;  in  this  an  interior  form  or  mandrel  is  used  instead  of  an 
exterior  shell  as  in  the  centrifugal  process,  and  after  fitting  on 


FIG.  84. 

this  the  steel  reinforcement,  a  fairly  dry  mixture  of  concrete 
is  mechanically  plastered,  as  it  were,  on  the  revolving  mandrel  in 
a  narrow  continuous  belt,  by  means  of  a  combination  of  con- 
veyor and  wrapping  of  canvas  under  tension,  wound  spirally  the 
length  of  the  pole.  Both  this  type  and  the  centrifugal,  have 
given  very  satisfactory  results  in  Europe. 

In  the  United  States,  to  the  best  knowledge  of  the  writer, 
there  is  at  the  present  time  no  installation  of  machine-made 
hollow  poles,  but  the  Oklahoma  Gas  &  Electric  Company  of 


REINFORCED  CONCRETE  CONSTRUCTION       145 

Oklahoma  City  has  developed  a  hand-molded  pole  of  hollow 
design  that  has  been  very  satisfactory  and  it  now  has  about  40 
miles  of  line  carried  on  this  type  of  pole,  mainly  for  city.dis- 


FIG.  85. — Centrifugal  type  concrete  poles. 

tribution  work,  though  some  transmission  line  is  included.     It 
has  some  poles  that  have  been  in  service  for  five  years  that  show 
no  apparent  depreciation. 
10 


146 


TRANSMISSION  LINE  CONSTRUCTION 


As  described  in  the  Electrical  World  for  May  25,  1911,  most 
of  the  poles  are  35  ft.  in  length  and  the  standard  dimensions 
for  this  size  are  7  in.  at  the  top,  and  16  in.  at  the  butt,  with  walls 
approximately  23/4  in.  thick;  these  poles  are  hexagonal  in 
section  and  are  reinforced  with  twelve  1/4-in.  twisted  or  mechan- 
ical bond  bars,  an  unusual  departure  from  other  processes  being 
to  maintain  these  rods  under  considerable  tension  during  the 
casting  of  the  pole  and  until  the  concrete  has  set  sufficiently 
hard  to  support  the  strain  itself. 


FIG.  86. — Oklahoma  Gas  &  Electric  Co.'s  concrete  poles. 

The  external  form  for  this  pole,  shown  in  Fig.  76,  is  made  of 
1/4-in.  galvanized  iron,  braced  with  transverse  ribs,  and  is  made 
in  sections;  the  internal  form  is  made  to  telescope  or  collapse 
within  itself  and  is  removed  as  soon  as  the  concrete  will  bear 
its  own  weight;  a  mixture  of  1  part  cement  to  2  parts  sand  and 
3  parts  crushed  stone,  is  used. 

This  type  of  pole  has  been  developed,  and  several  of  its  features 
patented,  by  F.  H.  Tidnam,  general  manager  of  the  Oklahoma 


REINFORCED  CONCRETE  CONSTRUCTION       147 

Gas  &  Electric  Company  and  has  been  adopted  by  that  company 
as  standard  for  the  construction  of  all  principal  lines.  Fig.  86 
shows  a  line  of  these  poles  used  for  city  distribution  work;  as  will 
be  noted  these  poles  are  not  stepped  as  is  the  case  in  many  installa- 
tions, extension  ladders  being  used  by  the  linemen  in  substi- 
tute thereof. 

Load  tests  of  concrete  poles  of  various  designs  have  been  very 
gratifying,  though  naturally  there  is  great  variation  in  results 
obtained,  as  would  be  expected  from  the  different  methods  of 
applying  the  reinforcing  steel  and  the  variety  of  concrete  mixes 
employed.  The  pole  built  by  the  Syracuse  Rapid  Transit  Com- 
pany for  trolley  purposes  was  given  a  thorough  test  as  noted  in 
the  Engineering  Record  for  Oct.  1,  1910.  This  pole  was  30  ft. 
long  with  6-in.  top  and  11-in.  butt  reinforced  as  previously 
described  and  set  6  ft.  in  the  ground;  load  was  applied  at  a  point 
3  ft.  down  from  the  top,  and  under  a  strain  of  1100  Ib.  the  deflec- 
tion was  3  in.;  and  with  1250-lb.  load,  this  increased  to  3  3/4  in.; 
the  pole  failed  at  3300  Ib.  The  failure  occurred  at  the  ground 
line  and  from  a  study  of  the  illustration  of  the  broken  section, 
accompanying  the  article  in  the  Engineering  Record,  it  appears 
that  the  spalling  off  of  the  concrete  from  the  buckling  of  the  rods 
on  the  compression  side  caused  the  failure  to  occur  at  a  lower 
load  than  would  have  been  the  case  if  the  reinforcement  had 
been  provided  with  transverse  ties  or  a  spiral  web  reinforcement. 
A  solid  30-ft.  pole  with  7-in.  top  and  12-in.  butt,  tests  of  which 
are  given  by  W.  M.  Bailey  of  Richmond,  Ind.  in  an  article  in 
Concrete  Engineering  for  March,  1909,  showed  better  results  as 
far  as  ultimate  strength  is  concerned,  than  the  Syracuse  pole. 
This  pole  was  reinforced  with  four  5/8-in.  high  carbon  twisted 
rods  " thoroughly  bound  together  with  No.  9  binding  wire"  to 
quote  the  original  article,  no  data  being  given  as  to  pitch  of  spiral. 
The  pole  mentioned  in  the  test  was  set  5  ft.  in  the  ground  and 
showed  the  following  characteristics  under  load: 

840    Ib.  applied  at  top  in  a  horizontal  direction 6-in.   deflection. 

1780    Ib.  applied  at  top  in  a  horizontal  direction 17-in.   deflection. 

2800    Ib.  applied  at  top  in  a  horizontal  direction 30-in.   deflection. 

(Slight  cracking  noted.) 
3640    Ib.  applied  at  top  in  a  horizontal  direction 36-in.   deflection. 

(Crushing  at  ground  line.) 
7200    Ib.  applied  at  top  in  a  horizontal  direction 60-in.   deflection. 

(Crushing  badly  at  ground  line.) 

The  pole  deflected  over  6  ft.  before  falling;  the  rods  did  not 


148  TRANSMISSION  LINE  CONSTRUCTION 

break,  the  failure  being  due  to  the  crushing  of  the  concrete.  It 
will  be  noted  that  this  pole,  containing  considerably  less  steel 
longitudinally,  though  of  somewhat  greater  cross-section  than 
the  Syracuse  pole,  showed  an  ultimate  strength  of  more  than 
two  times  that  of  the  same;  in  the  case  of  the  Syracuse  pole  a 
dynamometer  was  used  to  measure  the  load,  while  no  informa- 
tion was  given  as  to  the  means  of  determining  the  load  used  in  the 
Richmond  test. 

As  a  rough  comparison,  tests  of  single  poles  are  of  interest,  but 
in  structures  built  under  the  conditions  that  these  are,  the  average 
result  obtained  from  similar  tests  of  at  least  four  or  six  poles  is 
preferable,  and  is  the  only  fair  means  by  which  their  relative 
merits  can  be  determined. 

In  the  Cement  Age  for  Aug.,  1907,  comparative  tests  of  concrete 
and  cedar  poles  are  noted,  in  which  the  concrete  poles  showed 
quite  uniform  results;  in  this  case,  however,  only  two  concrete 
poles  were  tested  and  even  they  were  of  slightly  different  design. 
One  of  these  poles  was  octagonal  in  section  and  the  other  was 
square,  both  being  hollow  for  two-thirds  of  the  total  length, 
the  top  section  being  solid;  the  thickness  of  the  walls  of  the 
lower  two-thirds  varied  from  1  3/4  in.  to  3  in.  These  poles  were 
both  designed  for  a  load  of  about  1000  Ib.  applied  horizontally 
at  the  top,  and  were  figured  with  a  safety  factor  of  3;  the  oc- 
togonal  pole  was  8  in.  in  diameter  at  the  top  and  14  in.  at  the  butt, 
while  the  square  pole  was  7  in.  at  the  top  and  13  in.  at  the  butt; 
both  poles  were  30  ft.  overall  and  were  reinforced  with  four 
3/4-in.  and  four  5/8-in.  round  rods  24  ft.  long. 

With  the  poles  set  5  ft.  deep  in  concrete  bases  and  load  applied 
10  in.  down  from  the  top,  the  octagonal  poles  showed  a  deflection 
of  3  3/4  in.  at  the  top  when  under  a  load  of  1830  Ib.  and  broke 
at  the  ground  line  at  3150  Ib.  after  having  stood  3430  Ib.;  the 
square  section  pole  showed  a  deflection  of  2  1/2  in.  under  a  load 
of  1830  Ib.  and  failed  at  3690  Ib.  It  is  interesting  to  note  that 
the  two  cedar  poles  tested  in  comparison  with  the  concrete,  both 
white  cedar  of  8-in.  top  and  14-in.  butt,  30  ft.  long,  failed, 
respectively,  at  2530  Ib.  and  3490  Ib.  at  a  point  about  7  ft.  above 
the  ground  line;  the  wooden  poles  were  set  to  the  same  depth  and 
had  the  load  applied  at  the  same  point  as  the  concrete  poles. 

Many  tests  of  machine-cast  poles  are  recorded,  among  them  a 
series  on  some  of  the  centrifugal  type  conducted  by  the  Royal 
Mechanical  and  Technical  Institute  of  Dresden,  Germany,  as 


REINFORCED  CONCRETE  CONSTRUCTION      149 

noted  in  Cement  Age  for  March,  1911.  Three  poles  of  the  fol- 
lowing dimensions  were  tested:  length,  2$  ft.  6  in.;  top  diameter, 
inside  3.75  in.,  outside  5.9  in.;  butt  diameter,  5.5  in.  inside  and 
9.5  in.  outside;  the  materials  used  per  pole  were  70  Ib.  cement, 
539  Ib.  sand,  160  Ib.  water,  sixteen  1/4-in.  steel  rods  29  ft. 
6  in.  long,  and  fifteen  1/4-in.  rods  19  ft.  8  in.  long,  the  rods  being 
held  in  position  by  an  inner  and  outer  spiral  of  No.  11  wire  with 
a  screw  pitch  of  from  6  in.  to  8  in. 

The  first  pole  tested,  was  placed  horizontally  and  gripped 
5.9  ft.  from  the  butt  and  a  load  giving  a  deflection  of  3.6  in.  was 
applied  and  removed  repeatedly  without  showing  material 
permanent  set;  poles  Nos.  2  and  3  were  set  vertically  to  a  depth 
of  5.9  ft.  and  were  tested  with  horizontally  applied  loads,  the 
first  breaking  at  1195  Ib.  with  the  maximum  deflection  recorded 
of  45  1/8 in.  at  a  load  of  1175  Ib.,  and  the  second  at  1115  Ib.  with 
a  deflection  of  about  42  1/2  in.  at  1110  Ib. 

These  tests  show  a  greater  uniformity  than  those  of  solid  hand- 
cast  construction  without  fabricated  reinforcement,  as  might 
only  be  expected  from  a  consideration  of  the  respective  methods 
of  manufacture. 

In  the  Engineering  Record  for  Nov.  19,  1910,  a  test  of  a  Siegwart 
process  pole  is  noted.  This  pole  was  26.24  ft.  long,  7.5  in.  in 
outside  diameter  at  the  top  and  10  in.  at  the  butt,  with  walls 
about  1.2  in.  thick,  reinforced  with  thirty-two  1/4-in.  rods.  It 
was  tested  horizontally,  being  gripped  4  ft.  from  the  butt;  with 
550-lb.  load  the  deflection  was  2.2  in.  with  a  permanent  set  of 
0.16  in.,  with  1320-lb.  load  the  deflection  was  9.5  in.  with  a  perma- 
nent set  of  1.9  in.,  with  1690-lb.  load  the  deflection  was  17.9 
in.  and  the  permanent  set  8.3  in.,  the  pole  failed  finally  at  about 
1960  Ib. 

The  hollow  hexagonal  7-in.  top,  16-in.  butt,  35-ft.  poles  used  by 
the  Oklahoma  Gas  &  Electric  Company,  from  tests  made  on  line 
poles  in  place,  are  assumed  to  be  safe  for  a  horizontal  strain  of 
1500  Ib.  applied  at  the  cross-arm. 

Owing  to  the  great  weight  of  the  solid  type  of  concrete  poles, 
as  used  in  most  installations  in  this  country,  the  tendency  has 
been  to  use  them  in  the  shorter  lengths,  generally  from  30  ft.  to 
35  ft.,  with  a  few  exceptions;  with  the  development  of  several 
simple  practical  methods  of  casting  a  hollow  pole,  it  is  very 
likely  that  poles  of  greater  lengths  will  be  available  on  a  com- 
mercial basis  for  the  construction  of  cross-country  lines. 


150  TRANSMISSION  LINE  CONSTRUCTION 

The  6-in.  top,  9-in.  butt,  30-ft.  solid  poles  used  by  the  Mar- 
seilles Land  &  Water  Company  weighed  about  1700  Ib.  and  the 
60-ft.  poles  used  on  the  same  job,  which  were  constructed  with 
about  the  same  taper,  weighed  8500  Ib.;  the  Meadows  Division, 
Pennsylvania  Railroad  poles  weighed  about  5300  Ib.  for  the 
35-ft.  lengths  aud  17,300  Ib.  for  the  65-ft.  lengths;  the  35-ft. 
Welland  Canal  poles  weighed  about  5000  Ib.  and  the  50-ft. 
poles,  10,000  Ib.  each.  In  the  poles  used  for  trolley  work,  in 
6-in.  top,  11-in.  butt,  30-ft.  solid  pole  used  by  the  Syracuse  Rapid 
Transit  Company  weighed  about  2550  Ib.  each. 

In  the  hollow  design,  the  weights  of  the  poles  are  materially 
reduced  and  do  not  present  the  difficulties  of  erection  that  the 
solid  poles  do.  The  standard  35-ft.  7-in.  top,  16-in.  butt,  hexago- 
nal section  hollow  pole  of  the  Oklahoma  Gas  &  Electric  Company 
weighs  only  about  2000  Ib.,  550  Ib.  less  than  the  6-in.  top,  11-in. 
butt,  30-ft.  pole  of  the  solid  type  built  by  the  Syracuse  Rapid 
Transit  Company.  In  the  centrifugal  type  of  pole  much  data 
are  available  on  various  sizes  and  loadings  of  poles,  due  to  the 
fact  that  this  type  as  well  as  the  Siegwart,  has  been  manufactured 
in  commercial  competition  with  wood  and  steel  for  some  years 
past  and  naturally  many  different  standard  designs  have  been 
developed.  Below  are  given  specifications  and  price  list,  cover- 
ing sizes  and  loadings  for  a  few  typical  poles  such  as  would  be 
required  in  transmission  line  work  in  this  country,  the  data 
given  being  selected  from  the  specification  list  of  the  standard 
line  of  designs  manufactured  by  Otto  &  Schlosser  in  Germany,  as 
given  in  the  article  by  C.  H.  Furst  in  Cement  Age  for  March,  1911. 

It  will  be  noted  that  these  poles  are  rated  with  a  factor  of 
safety  of  5,  whereas  4  is  usually  considered  ample  in  this 
country,  and  the  completeness  of  the  whole  data  shows,  that  a 
closer  study  of  the  practical  considerations  involved  in  the 
design  of  this  class  of  structure  has  been  made  in  Europe,  than 
has  been  the  case  with  the  builders  of  poles  in  this  country. 
Except  in  a  few  isolated  cases,  little  attention  has  been  given 
here  to  the  working  out  of  an  economical  design  for  a  stated 
loading  with  a  set  factor  of  safety,  the  usual  aim  of  the  builders 
being  directed  to  the  production  of  a  substitute  for  an  existing 
type  of  construction  by  cut  and  try  methods.  This  accounts 
for  the  paucity  of  reliable  data  as  to  assumptions  and  computa- 
tions made  for  various  designs;  in  the  matter  of  costs,  however, 
information  is  more  definite. 


REINFORCED  CONCRETE  CONSTRUCTION       151 


Outside 

Thickness 

diameter, 

of  walls, 

Working 

Length,                 in. 

in.             load.    Safety 

Weight, 

fv»c+ 

ft.  in. 

factor 

Ib. 

i 

i 

of  5  Ib. 

Top      Butt 

Top 

Butt 

j 
32  10           7.5 

13.4 

1.97 

3.15 

1100 

2310 

$15.76 

39     4 

7.5 

14.6 

2.36 

3.15 

1100 

3190 

18.58 

42    8 

6.9 

14.6 

2.36 

3.15 

1100 

3465 

21.74 

46     0 

6.3 

14.6 

2.36 

3.15 

1100 

3740 

24.86 

32  10 

7.5 

13.4 

1.97 

3.15 

1540 

2530 

20.00 

39     4           7.5 

14.6 

2.36 

3.15 

1540 

3696 

22.82 

'42     8           6.9 

14.6 

2.36 

3.15 

1540 

3850          27.16 

46     0           6.3 

14.6 

2.36 

3.15 

1540 

4180       !  31.26 

37     9           8.0 

14.6 

2.36 

3.15 

1760 

3630       I  22.50 

32  10 

8.7 

14.6 

2.36 

3.54 

2420 

3360          22.18 

In  the  solid  type,  the  30-ft.  poles  of  the  Fort  Wayne  &  Wabash 
Valley  Traction  Company  were  made  under  a  contract  price 
of  $7.50  each,  while  the  6-in.  top,  11-in.  butt,  30-ft.  poles  of  the 
Syracuse  Rapid  Transit  Company  were  built  by  the  company 
for  $10.39  each;  it  may  be  noted,  however,  that  the  latter  poles 
were  more  heavily  reinforced  than  the  former,  about  125  Ib. 
more  steel  being  used.  The  manufacturing  cost  of  the  Oklahoma 
Gas  &  Electric  Company  design  of  hexagonal  hollow  pole  is 
given  as  $6  for  the  25-ft.  size,  and  $8.50  for  the  7-in.  top,  16-in. 
butt,  35-ft.  size;  compared  with  the  centrifugal  type  of  about 
the  same  characteristics  (see  Cement  Age  for  March  1911,  page 
146),  it  appears  that  this  hand-cast  pole  can  be  built  at  a  cost 
closely  approximating  that  of  machine-molded  types.  There 
is  a  great  difference  in  manufacturing  output,  however,  between 
the  two  processes;  with  a  set  of  forms  costing  $45  each  and  an 
equipment  of  fourteen  sets,  with  seven  cores,  a  gang  of  five  men 
can  turn  out  from  seven  to  eight  poles  of  the  35-ft.  Oklahoma 
City  type  each  day,  while  in  the  German  factory  where  the 
centrifugal  type  of  pole  is  manufactured,  a  crew  consisting  of 
one  foreman,  eight  men,  and  four  boys,  operating  one  machine, 
will  turn  out  about  25  poles  per  day.  From  this  comparison 
it  is  evident  that  with  the  same  amount  of  labor,  the  machine 
method  is  considerably  more  rapid,  but  the  increase  in  output 


152  TRANSMISSION  LINE  CONSTRUCTION 

is  offset  by  the  greater  fixed  charges  of  the  machine  plant  equip- 
ment, and  the  expense  for  power,  maintenance,  etc. 

The  cost  of  handling  any  type  of  concrete  pole  is  a  serious 
handicap  to  its  use  in  transmission  line  work,  especially  in  a 
rough  country  and  in  isolated  regions,  and  it  may  be  safely  said 
that  its  use  for  country  work,  at  the  best  will  be  limited  to  some 
form  of  the  hollow  type.  Concrete  poles,  if  manufactured  at 
a  central  point,  could  be  shipped  as  easily  as  structural  steel 
poles  as  the  same  facilities  would  be  required  in  either  case, 
and  they  could  be  unloaded  and  stored  just  as  well,  derricks 
being  used  for  all  handling;  in  weight,  however,  they  will  run 
about  two  or  three  times  as  heavy  as  the  same  length  of  steel 
poles  for  equal  safe  load  rating. 

The  transportation  and  handling  of  the  poles  for  distribution 
is  the  most  serious  feature  and  it  would  seem  that  some  form 
of  long-coupled  wagon  equipped  with  rollers  at  the  points  of 
support  for  the  poles,  or  an  ordinary  wagon,  with  a  gin  wagon 
stationed  in  the  field  to  unload  the  poles,  will  have  to  be  used; 
in  many  cases  it  is  possible  that  poles  .can  be  molded  at  the  pole 
locations  more  economically  than  in  a  yard,  but  the  conditions 
are  so  much  better  for  uniformity  where  the  poles  are  all  cast 
in  central  yards,  that  the  advantage  may  be  negative. 

No  general  cost  data  are  available  for  the  delivery  of  poles  in 
the  field  under  average  transmission  line  conditions,  but  for  such 
as  would  obtain  in  the  Middle  West  with  fair  dirt  roads  and 
an  average  haul  of  5  miles  or  6  miles,  the  distribution  cost  per  pole 
on  the  basis  of  35-ft.  poles  weighing  about  2000  Ib.  will  be  about 
$3  to  $5  each;  as  noted  in  the  Engineering  Record  for  Oct.  1, 
1910,  the  cost  for  the  distribution  of  the  30-ft.  poles  used  by 
the  Fort  Wayne  &  Wabash  Valley  Traction  Company  from  yard 
to  pole  location,  ready  for  erection,  was  $2  each;  it  is  probable 
that  these  poles  were  hauled  out  on  flat  cars,  rigged  for  the 
economical  unloading  of  the  poles  at  their  sites.  In  general, 
where  concrete  poles  are  used  in  their  natural  field  for  trans- 
mission work,  that  is,  for  lines  with  35-ft.  or  40-ft.  poles  in  200-ft.  or 
300-ft.  spans  as  standard,  with  the  line  built  along  highways 
or  through  fairly  level  country,  the  matter  of  distribution  can 
be  worked  out  satisfactorily. 

With  the  favorable  conditions  for  distribution  and  setting 
that  obtain  with  them,  electric  railways  will  probably  find  the 
use  of  concrete  poles  for  combination  trolley  and  transmission 


REINFORCED  CONCRETE  CONSTRUCTION       153 

work  to  be  economical  and  it  will  probably  be  in  this  line  that 
such  poles  will  find  their  greatest  development;  it  will  be  noted 
that  the  two  foremost  examples  of  transmission  lines  utilizing 
concrete  construction,  are  those  built  where  the  natural  con- 
ditions especially  lent  themselves  to  the  cheap  handling  and 
erection  of  this  type  of  work.  In  the  case  of  the  Marseilles, 
111.  line  with  nearly  30  miles  of  33,000-volt  construction,  the  poles 
were  cast  in  a  yard  adjacent  to  a  canal,  loaded  with  the  yard 
derrick  directly  to  a  barge,  floated  on  this  to  their  locations, 
and  set,  in  most  cases,  by  means  of  a  derrick  erected  on  the  barge; 
the  crew  consisted  of  a  foreman  and  eight  men  and  normally 
about  twenty  poles  per  day  were  set,  the  spacing  being  about 
125  ft.  The  conditions  at  the  Welland  Canal  also  were  favor- 
able to  the  handling  of  heavy  poles,  though  not  allowing  the 
methods  followed  out  at  Marseilles. 

Where  30-ft.  to  40-ft.  poles  have  been  set  under  average  condi- 
tions, a  gin  wagon,  such  as  is  used  for  the  erection  of  wooden  poles 
and  with  about  the  same  crew,  has  been  used.  The  cost  of  setting 
30-ft.  poles  of  the  solid  type,  in  100-ft.  to  125-ft.  spans,  is  given  by 
the  Fort  Wayne  &  Wabash  Valley  Traction  Company  as  $1.62 
each,  a  gin  pole  or  a  gin  wagon  being  used;  the  Oklahoma  Gas 
&  Electric  Company  gives  the  cost  of  building,  hauling  and  set- 
ting, including  cost  of  steel  cross-arms  and  pins,  of  its  standard 
35-ft.  poles,  at  $18  each,  estimating  that  the  cost  of  its  concrete 
construction  is  about  50  per  cent,  greater  than  that  of  wood. 
Typical  views  of  the  setting  of  an  Oklahoma  City  pole,  secured 
through  the  courtesy  of  J.  M.  Brown,  superintendent  of  lines 
for  the  Oklahoma  Gas  &  Electric  Company,  are  shown  in  Fig. 
87,  a,  b,  c,  d,  e,  f,  g,  h. 

Concrete  poles,  properly  constructed  and  adapted  to  the 
proper  conditions,  will  undoubtedly  be  used  to  an  increasing 
extent;  early  doubts  as  to  their  ability  to  withstand  the  ravages 
of  frost  and  the  elements,  appear  to  have  been  somewhat  removed, 
as  they  have  shown  practically  no  discernible  depreciation 
where  they  have  been  in  service  for  several  years.  In  one 
instance  that  has  been  brought  to  the  attention  of  the  writer, 
poles  reinforced  with  a  mechanical  bond  bar,  that  had  been  in 
service  for  a  few  years  were  cut  off  at  the  butt  for  examination 
and  revealed  the  fact  that  the  concrete  surrounding  the  bars  was 
crumbled  and  powdered,  leaving  the  steel  loose,  but  on  the  other 
hand,  the  experience  of  the  Oklahoma  Gas  &  Electric  Company, 


154  TRANSMISSION  LINE  CONSTRUCTION 


REINFORCED  CONCRETE  CONSTRUCTION       155 

from  examination  of  several  of  its  early  poles  that  were  taken 
down  for  that  purpose,  is  that  the  interior  of  the  pole  was  dry 
and  the  steel  unchanged;  these  conflicting  experiences  may  be 
due  to  poor  concrete  in  the  first  case,  but  this  feature  merits 
further  investigation.  The  effect  of  lightning  on  concrete  poles 
has  not  in  the  actual  cases  noted  up  to  this  time,  been  serious, 
though  spalling  off  of  the  concrete  from  the  bars  from  this  cause 
has  been  noted. 

Taking  all  things  into  consideration,  the  pioneer  work  in 
concrete  construction  has  so  far  been  satisfactory,  but  with  the 
high  average  cost  of  these  poles  in  place,  bearing  in  mind  also  the 
uncertainty  as  to  their  ultimate  life,  they  can  hardly  yet  be 
treated  as  on  a  par  with  other  types  of  construction  for  work  of 
any  magnitude. 


CHAPTER  VIII 

SPECIAL  STRUCTURES 

In  almost  any  transmission  line  project  conditions  are  encoun- 
tered for  which  the  standard  type  of  structure  is  not  suitable  and 
cannot  well  be  used;  this  applies  for  all  materials,  wood,  concrete 
and  steel,  and  either  special  combinations  of  the  standard  mate- 
rials are  developed  or  entirely  new  designs  are  worked  out  to  meet 
with  the  demands  of  the  extraordinary  conditions  that  arise. 


FIG.  88. — Transposition  fixture — wooden  pole  work. 

The  transposition  of  the  conductors  of  high-tension  lines  is 
generally  effected  by  the  use  of  a  special  structure,  though  in  the 
case  of  lines  built  with  good  conductor  clearance,  transpositions 
are  sometimes  made  without  any  change  from  the  standard 

156 


SPECIAL  STRUCTURES 


157 


FIG.  89. — Transposition  tower — single  circuit  construction. 


158  TRANSMISSION  LINE  CONSTRUCTION 

construction.  A  form  of  special  structure  used  in  wooden  pole 
work  is  shown  in  Fig.  88;  in  this  structure  two  standard  poles  and 
standard  fittings  all  the  way  through  are  used;  a  fixture  of  this 
kind  has  often  been  set  with  the  spans  on  either  side  only  about 
half  the  standard  length,  though  in  many  cases  there  is  no  reason 
why  the  regular  spacing  cannot  be  used,  as  for  instance  in  the 
ordinary  short-span  construction  where  the  conductor  spacing 
is  relatively  great.  The  disadvantage  of  a  two-pole  structure 
is  that  it  cannot  ordinarily  be  used  where  lines  are  built  on 
public  highways  and  for  that  reason  transpositions  in  wooden 


FIG.  90. — Transposition  tower — double  circuit  construction. 

pole  line  work  are  often  made  without  any  special  provisions. 
In  steel  tower  work  special  structures  are  generally  employed 
and  are  set  midway  between  two  standard  line  towers;  Figs. 
89  and  90  show  typical  arrangements  followed  out  in  single- 
circuit  and  double-circuit  construction;  as  will  be  noted,  the 
principle  of  revolving  the  delta  60  degrees  is  the  same  as  used  in 
wooden  pole  work.  In  Fig.  91  is  shown  a  method  of  transposi- 
tion that  is  somewhat  akin  to  methods  employed  in  telephone 
work;  a  standard  anchor  tower,  excepting  for  the  middle  cross- 
arm,  is  used  and  the  conductors  are  dead-ended  to  the  regular 


SPECIAL  STRUCTURES 


159 


strain  insulators,  the  jumpers  instead  of  bridging  the  insulators 
as  in  straight  construction,  crossing  over  to  make  the  transposi- 
tion as  shown  in  the  illustration.  This  type  of  transposition  has 
the  advantage  of  requiring  only  a  standard  strain  tower  with  a 
slight  modification  and  there  is  no  crossing  of  conductors  in  mid- 
span  as  occurs  where  transpositions  are  made  in  the  ordinary  way. 
In  wooden  pole  work  the  cost  of  a  two-pole  fixture  as  described, 
complete  in  place,  will  average  about  twice  the  cost  of  a  standard 


FIG.  91. — Transposition — dead-end  and  jumper  type. 


line  pole  of  the  same  height  erected  in  the  course  of  the  regular 
work.  In  steel  tower  work  the  cost  of  transposition  structures 
along  the  line  of  those  illustrated  will  cost  from  10  per  cent,  to  20 
per  cent,  more  than  a  standard  straight-line  tower,  except  in  the 
case  of  the  tap  transposition,  where  the  structure,  with  the  slight 
changes  necessary,  ought  not  to  be  more  expensive  than  the 
regular  ptrain  or  anchor  design. 

The  crossing  of  rivers,  bays,  etc.,  in  long  spans  calls  for  special 


L60          TRANSMISSION  LINE  CONSTRUCTION 


Where  Kequired 
Double-Arm  and 
use  Double  Diag- 
onal Bracing. 


FIG.  92. — Double  A-frame  structure. 


FIG.  93. — River  crossing  tower. 


SPECIAL  STRUCTURES 


161 


construction  of  great  strength,   conditions  being  most  severe 
where  navigable  water  courses  must  be  crossed. 

In  wooden  pole  work,  structures  built  up  of  standard  poles  of 
the  required  length  will  be  generally  satisfactory  except  in  cases 
of  unusually  long  spans  where  the  sag  required  will  necessitate  the 


FIG   94. — Welland  Canal  crossing — Ontario  Hydro-Electric  Power 
Commission. 

use  of  a  greater  length  of  pole  than  economical,  or  where  a  navi- 
gable clearance  demands  a  structure  of  comparatively  great 
height;  for  average  long-span  work,  a  tower  built  up  of  four 
poles  set  vertically  and  provided  with  suitable  cross-arming  and 
bracing  has  been  used  much,  but  a  combination  of  two  A- 
11 


162 


TRANSMISSION  LINE  CONSTRUCTION 


fixtures  set  either  as  shown  in  Fig.  92  or  at  right  angles  thereto, 
gives  a  better  arrangement;  where  there  is  a  combination  of  low 
banks  and  a  quite  long  span,  or  where  a  navigable  stream  is  to 
be  crossed,  a  steel  structure  will  usually  be  required. 


FIG.  95. — River  crossing  structure. 

In  Fig.  93  is  shown  the  top  arrangement  of  a  steel  tower 
used  to  carry  three  1/2-in.  Siemens-Martin  cables  in  a  1200-ft. 
span;  these  towers  were  60  ft.  high  and  have  a  base  spread  of 
18  ft.;  the  cost  of  one  river  tower  in  place  is  given  as  $1375  and 


SPECIAL  STRUCTURES 


163 


that  of  the  complete  river  span,  $3258,  including  all  labor  and 
material.  In  Fig.  94  are  shown  the  special  towers  used  by  the 
Ontario  Hydro-Electric  Power  Commission  in  crossing  the  Well- 
and  Canal;  these  towers  were  designed  to  give  150  ft.  clearance 


~1 


FIG.  96. — River  crossing  structure. 

for  vessels  and  weighed  about  50,000  Ib.  each;  they  were  erected 
on  reinforced  concrete  foundations. 

In  Figs.  95  and  96  are  shown  a  type  of  long-span  river-crossing 
structures  that  have  been  developed  by  the  Archbold-Brady 
Company,  Syracuse,  N.  Y.,  the  first-mentioned  being  made  up 


164 


TRANSMISSION  LINE  CONSTRUCTION 


with  rolled  sections  for  the  main  members  and  the  latter  with 
built-up  sections  for  these  parts;  the  tower  shown  in  Fig.  95 
carries  two  three-phase  25,000-volt  circuits  of  5/8-in.  nineteen- 
strand  special  plough-steel  cable  in  crossing  the  Susquehanna 
River  near  Berwick,  Pa.,  with  a  span  of  about  2200  ft.;  the 
towers  for  this  crossing  were  designed  for  a  working  load  of 
12,000  Ib.  per  conductor.  The  structure  shown  in  Fig.  96  is 
70  ft.  high,  from  the  top  of  the  tower  to  the  top  of  the  concrete 
base  and  carries  a  1000-ft.  span  of  two  three-phase  circuits  of 
1/2-in.  high  strength  steel  strand,  with  a  maximum  strain  of  8500 
Ib.  per  cable  allowed  for.  The  advantage  of  the  type  of  structures 
just  described  is  that  they  are  easy  to  erect  and  the  field  expense 
is  very  low  compared  with  that  for  other  types. 


Fi  i.  97. — Disconnecting  switch 
structure. 


FIG.  98. — Burke  switch  mounting 


In  the  past  few  years  another  kind  of  special  structures  has 
been  demanded  in  transmission  line  work — towers  for  the  mount- 
ing of  high-tension  line  switches.  The  main  considerations  in 
the  design  of  a  switch  tower  are  those  of  operating  clearances 
between  opposite  phases  and  the  mechanical  conditions  imposed 
are,  as  a  rule,  simple;  the  clearance  required  will  depend  upon 
whether  the  switch  is  to  be  operated  dead  or  alive,  and  if  it  is 
to  be  used  for  live  circuits,  whether  it  is  to  open  a  loaded  circuit 
or  only  the  charged  line. 

Where  the  switches  are  more  a  line  disconnecting  switch, 
intended  mainly  to  be  opened  dead  or  with  very  little  line  cur- 
rent on,  a  regular  vertical  breaking  hinged  switch,  mounted  as 


SPECIAL  STRUCTURES  165 

shown  in  Fig.  97,  is  often  used;  the  supporting  structure  here 
consists  merely  of  two  double-armed  standard  poles,  with  the 
arms  on  which  the  switches  are  mounted,  arranged  between 
them.  Where  line  current  of  any  magnitude  or  a  loaded  circuit 
is  to  be  opened,  switches  with  either  a  horizontal  or  vertical  break, 
provided  with  horns  should  be  used;  for  the  support  of  this  kind 
of  a  switch  considerable  clearance  must  be  provided  between 
center  lines  since  the  arc  on  breaking  the  circuit  is  necessarily 


FIG.  99. — Burke  switch  mounting. 

heavy.     The  designs  of  the  various  types  of  switches  of  this 
character  will  be  discussed  later. 

Figs.  98  and  99  show  typical  wooden  pole  mountings  of  a 
Burke  outdoor  switch,  the  first  named  for  22,000  volts  and 
including  a  high-tension  fuse;  the  latter  for  11,000  volts  and 
including  fuse,  choke  coils,  and  arrester  gaps  for  an  outdoor 
sub-station;  Fig.  100  shows  the  framing  for  a  Pacific  Electric 
&  Manufacturing  Company  Baum  type  switch  as  generally 


166 


TRANSMISSION  LINE  CONSTRUCTION 


used  for  disconnecting  purposes  on  60,000-volt  lines;  the  three 
insulators  comprising  each  switch  unit  are  now  mounted  on 
steel,  as  shown  in  Fig.  105,  instead  of  on  a  wooden  arm  and  where 
the  load  is  to  be  interrupted,  the  spacing  between  switches  is 


Note:-  Where  Dead  End 
Insulator  is  not  to 
be  used  Saw  18"off 
Respective  End  of 
Cross  Arm. 


Coupling 


Shaft-* 


Handle 

\ 


-10-9- 


-Pole  10  Top 


Ground 
Wire 


FIG.   100. — Baum  switch  mounting. 

increased  about  30  per  cent,  and  horns  are  provided,  as  shown 
in  the  cut. 

The  steel  disconnecting  switch  structure  shown  in  Fig.  101 
is  practically  a  standard  strain  tower  for  the  line  in  question 
arranged  for  the  mounting  of  the  switches;  Figs.  102  and  103 
show  the  disconnecting  switch  structures  with  suspension  in- 


SPECIAL  STRUCTURES 


167 


sulators,  used  on  the  Central  Colorado  Power  Go's,  system;  in 
Fig.  104  is  illustrated  the  type  of  structure  used  for  the  sup- 
port of  "Kilarc"  switches. 

As  previously  noted,  switches  for  the  opening  of  a  heavy 
charging  current  or  a  loaded  circuit  should  be  arranged  not  only 
to  rupture  the  arc  safely,  but  to  prevent  its  re-formation  after 
being  once  broken;  this  is  accomplished  in  all  the  outdoor 
air-break  switches  by  means  of  horns  to  which  the  arc  is  trans- 
ferred upon  breaking  the  contact  at  the  clips;  the  operation 


FIG.  101. — Disconnecting  switch  tower. 

of  the  horn  gaps  being  the  same  as  in  the  case  of  lightning 
arresters.  Outside  of  the  common  use  of  horns,  the  mechanical 
features  of  the  different  switches  vary  considerably. 

In  the  Burke  switch,  shown  in  open  and  closed  positions  in 
Figs.  105  and  106,  a  single  horizontal  break  is  made  with  a  two- 
insulator  rotating  unit;  this  is  noteworthy  in  that  there  is  no 
torsional  strain  between  the  pin  and  the  insulator  as  occurs 
where  one  insulator  is  used  under  such  conditions,  and  the 
alignment  of  the  blade  can  be  maintained  in  better  shape  also. 
The  Baum  switch  shown  in  Figs.  107  and  108,  employs  a  double 
horizontal  break,  the  latter  design,  provided  with  a  special 


168 


TRANSMISSION  LINE  CONSTRUCTION 


contact  mechanism,  being  used  for  100,000-volt  service;  this 
special  contact  mechanism  consists  of  an  arrangement  for  with- 
drawing the  contact  blades  from  the  clips  in  a  direction  parallel 
to  the  line  by  means  of  short  levers  working  on  a  6-in.  radius; 
after  this  system  of  levers  has  reached  the  end  of  its  travel,  the 
main  arm  is  engaged  and  swung  around;  this  method  of  with- 


FIG.   102. — Disconnecting  switch  tower. 

drawing  the  blades  from  the  clips  obviates  trouble  due  to  the 
"sticking"  of  switches  which  have  been  closed  for  some  time. 
The  "Kilarc"  switch,  which  is  shown  in  Fig.  109,  a,  6,  c}  opens 
vertically,  transferring  the  arcs  to  the  horns;  this  switch  has 
been  developed  with  a  view  to  the  handling  of  loads  of  great 
capacity,  one  of  the  types  being  rated  at  20,000  k.w.  for  110,000- 
volt  service.  Fig.  109,  a,  shows  a  standard  hand-operated 


SPECIAL  STRUCTURES 


169 


60,000-volt  switch;  109,  6,  an  overload  automatic  circuit-breaker, 
and  109,  c,  an  insulator  for  a  150,000-volt  switch  in  course  of 
construction  (May,  1912). 

All  of  the  switches  described  are  arranged  for  the  simultaneous 
opening  of  all  three  phases  by  a  system  of  levers  and  rods  or 
chains  operated  from  a  platform  or  from  the  ground. 

In  the  foregoing  paragraphs  note  has  only  been  made  of 
switch  structures  as  would  be  used  in  sectionalizing  lines,  etc. 


FIG.  103. — Dead-end  switch  tower  with  insulated  platform. 

(simple  isolated  tower  structures),  but,  as  a  matter  of  fact,  there 
are  many  installations  of  outdoor  switching  and  junction 
stations  where  the  structural  framing  for  the  mounting  of  the 
appliances  is  larger  than  most  stations  and  which  cost  thousands 
of  dollars  where  the  simple  switch  will  cost,  hundreds.  A 
typical  structure  of  this  class  is  shown  in  Fig.  110. 

The  framing  for  a  one-pole  switch  support  erected  complete 
will  cost  ordinarily  about  one  and  one-half  times,  and  a  two-pole 
support,  about  three  times  the  cost  of  a  standard  line  pole  of 
the  same  size  in  place;  a  steel  tower  will  cost  about  25  per  cent. 


170  TRANSMISSION  LINE  CONSTRUCTION 


FIG.   104. — Kilarc  switch  mounting. 


FIG.  105. — Burke  switch — open. 


SPECIAL  STRUCTURES 


171 


FIG.   106. — Burke  switch — closed. 


FIG.  107. — Baum  switch. 


172 


TRANSMISSION  LINE  CONSTRUCTION 


Jl    I          &S—~^Ml^ »»          |    jll 

,     Jpatt.  DLjJ                      U     , 
[* —     — 4 — t-i-i —        — Jjl tjL-iL^: j 

FIG.   108. — Baum  100,000-volt  switch. 


FIG.  109a. — Kilarc  switch. 


SPECIAL  STRUCTURES  173 

to  75  per  cent,  more  than  a  standard  line  tower  of  the  same 
height,  depending  upon  the  amount  of  special  framing  required 
by  the  switch  itself. 

The  cost  of  the  switches  themselves  will  vary  considerably 
for  the  same  service  with  the  different  makers;  one  of  the  stand- 
ard types  will  cost  about  $80  for  a  three-phase  45,000-volt  unit 
and  about  $350  for  100,000  volts,  f.o.b.  factory,  complete  with 
insulators. 


FIG.   1096. — Kilarc  automatic  circuit  breaker. 

For  tapping-off  branch  lines,  splitting  circuits,  etc.,  special 
junction  towers  are  employed.  In  wooden  pole  work  without 
switches  a  four-post  structure  such  as  those  illustrated  in  Figs. 
Ill  and  112  is  generally  used;  in  steel  construction,  junction 
towers  will  be  found  in  all  types,  ranging  from  two  standard 
line  towers  set  close  together  with  a  little  special  cross-arm 
framing  in  between,  to  elaborate  structures  of  great  size  such 
as  shown  in  Fig.  110.  Fig.  113  shows  the  method  of  bringing  the 
140,000-volt  line  of  the  Au  Sable  Electric  Company  into  its 
Zilwaukee  sub-station,  using  two  dead-end  towers  and  swinging 
to  a  third  structure. 


174          TRANSMISSION  LINE  CONSTRUCTION 


FIG.   109c. — Insulation  for  150,000  volt  Kilarc  switch. 


FIG.  110. — Out-door  switching  station. 


SPECIAL  STRUCTURES  175 

Dead-end  towers  to  take  the  terminal  strain  at  stations,  etc., 
are  similar  to  line  anchor  towers  ordinarily,  except  that  where 
bought  specially  for  certain  locations,  they  may  be  designed  to 
handle  strains  from  a  specified  direction  only.  Dead-ends  in 
wooden  construction  are  usually  made  on  a  four-post  structure 
similar  to  the  junction  towers  illustrated,  suitable  arming  and 
bracing  being  provided  according  to  the  span  and  size  of  con- 
ductor, or  on  a  double  A-frame  as  shown  in  Fig.  92. 


FIG.   111. — Wood  pole  junction  or  dead-end  structure. 

In  the  crossing  of  railroad  rights-of-way,  special  construction 
is  usually  called  for;  there  is,  however,  a  great  lack  of  uniformity 
in  the  requirements  of  the  different  roads  so  that  the  same 
transmission  system  may  have  two  or  three  different  types  of 
crossing  construction,  depending  upon  the  number  of  railroad 
systems  crossed.  In  the  past  a  basket  or  cradle  construction 
supported  beneath  the  line  conductors  so  as  to  catch  a  broken 


176 


TRANSMISSION  LINE  CONSTRUCTION 


high-tension  wire  as  it  fell,  has  been  often  demanded  by  the  rail- 
road authorities;  after  observing  the  operation  of  this  as  a 
protective  device,  especially  in  the  winter  time  when  it  was 
liable  to  be  dangerously  loaded  with  sleet  and  snow,  its  value 
has  been  questioned  and  it  has  now  come  to  be  regarded  as  a 
doubtful  means  of  protection. 

Several  disconnecting  devices  have  been  offered  as  a  solution 
for  this  problem,  in  which  the  conductor  is  dead-ended  to  a 
lug  that  is  held  safely  in  contact  with  a  clip  or  casting  clamped 


FIG.   112. — Wood  pole  junction  or  dead-end  structure. 

to  the  insulators,  as  long  as  the  strain  in  the  crossing  span  is 
maintained,  but  which,  upon  the  failure  of  this  strain,  as  would 
occur  when  a  wire  breaks,  drops  out  and  with  the  broken  section 
of  wire  falls  to  the  ground;  in  one  of  these  types,  the  lug  drops 
out  by  the  force  of  gravity  and  in  another  it  is  expelled  by  a 
spring.  These  test  out  very  well  but  have  been  objected  to  by 
railroads  in  localities  where  sleet  occurs,  on  the  ground  that  the 
lugs  might  be  frozen  in  and  fail  to  clear.  Several  schemes  for 
grounding  broken  conductors  have  also  been  tried  out  but  have 
not  been  satisfactory. 


SPECIAL  STRUCTURES 


177 


f 


12 


178          TRANSMISSION  LINE  CONSTRUCTION 


FIG.  114. — Railroad  crossing — Ontario  Hydro-Electric  Power 
Commission  lines. 


FIG.  115. — Joint  tower  at  crossing  of  two  high-tension  lines. 


SPECIAL  STRUCTURES 


179 


The  method  of  making  a-  crossing  that  is  now  beginning  to  be 
regarded  as  the  most  practicable  is  for  the  transmission  com- 
pany to  build  the  work  in  as  short  a  span  as  possible  and  as  well 
as  possible  without  any  attempt  to  catch  broken  conductors  or 
to  disconnect  them  in  case  of  trouble,  in  other  words,  to  figure 
that  there  are  to  be  no  broken  wires. 

Along  these  lines  specifications  have  been  drawn,  limiting  the 
size  of  line  wires  in  one  case  to  No.  0  for  copper  and  No.  00  for 
aluminum,  calling  for  double  insulators,  arcing  sleeves  or 
serving  of  No.  6  wire  for  24  in.  on  either  side  of  insulators,  and 


FIG.  116. — Corner  tower — 140,000  volt  line  of  Au  Sable  Power  Co. 

requiring  structures  of  a  certain  factor  of  safety  for  the 
different  materials  and  designed  to  give  a  clearance  of  25  ft.  to 
35  ft.  from  the  top  of  the  rail  to  the  lowest  wire  at  a  certain 
maximum  temperature. 

In  Fig.  114  is  shown  a  typical  railroad  crossing  on  the  Ontario 
Hydro-Electric  Power  Commission  system;  the  towers  are  the 
standard  anchor  structures  and  the  equipment  the  same  as  at 
regular  strain  tower  installations. 


180 


TRANSMISSION  LINE  CONSTRUCTION 


In  the  crossing  of  telephone,  telegraph,  or  other  lines,  the  same 
general  conditions  as  to  the  character  of  the  construction  neces- 
sarily hold  good.  It  often  occurs,  however,  that  better  means 
present  themselves;  in  the  case  of  a  wooden  pole  line  crossing  a 
telephone  line,  for  instance,  a  line  pole  can  be  set  on  either  side 
close  up  to  the  telephone  line  and  make  what  is  known  as  a 


FIG.  117. — Corner  construction — Ontario  Hydro-Electric  Power 
Commission  lines. 

short-span  crossing,  wherein  the  height  of  the  line  poles  and  the 
length  of  the  span  are  such  that  if  a  wire  breaks  it  will  be  too 
short  to  reach  down  to  the  telephone  wires;  with  a  crossing  of 
this  type  it  will  require  the  failure  of  both  supports  for  the  high- 
tension  wires  to  come  in  contact  with  the  telephone  line;  horns 
should  be  provided  at  the  ends  of  the  cross-arms  to  catch  a 
conductor  in  the  event  of  the  failure  of  the  tics  on  both  poles. 


SPECIAL  STRUCTURES  181 

In  long-span  tower  work,  it  is  obvious  that  the  foregoing  method 
of  crossing  protection  will  be  found  very  expensive,  and  is  not 
resorted  to;  an  arrangement  that  has  been  used  in  several  cases 
has  been  to  set  a  line  tower  so  as  to  "straddle"  the  telephone 
line  and  carry  the  same  through  the  structure  on  cross-arms 
bolted  to  convenient  braces,  providing  suitable  projecting  arms 


FIG.  118. — Corner  construction — Ontario  Hydro-Electric  Power 
Commission  lines. 

on  each  side  of  the  tower  to  catch  and  ground  a  falling  conductor. 
This  method  has  been  objected  to  in  some  instances  but  with 
good  construction  ought  to  be  satisfactory. 

In  considering  both  railroad  and  line  crossings,  it  will  be  well 
to  note  the  stringent  requirements  which  must  be  fulfilled  in 
Europe  in  this  line;  in  cases  noted  by  the  writer,  the  protec- 
tion amounted  practically  to  the  building  of  an  aerial  tunnel  for 


182 


TRANSMISSION  LINE  CONSTRUCTION 


either  the  telephone  and  telegraph  line,  or  for  the  high-tension 
conductors;  in^the  description  of  the  Lauckhammer  110,000- 
volt  line,  already  noted  as  the  first  line  of  that  voltage  in  Europe, 
the  Elektrotechnische  Zeitschrift  for  Aug.  31,  1911,  illustrates  the 
structure  used  for  the  protection  of  a  railroad  crossing,  which  is 
typical  of  what  appears  to  be  often  demanded. 


r 


FIG.  119. — Special  heavy-angle  tower- 


>sac  Tunnel  electrification. 


The  crossing  of  one  high-tension  line  by  another  is  a  problem 
in  line  construction  that  has  been  encountered  in  very  few  in- 
stances and  only  in  the  past  few  years.  The  method  of  short- 
spanning  may  be  used,  or  a  joint  structure  may  be  provided  at 


SPECIAL-STRUCTURES  183 

the  crossing  point  arranged  to  carry  the  two  lines  so  that  either 
will  be  safely  accessible  while  the  other  is  alive.  In  Fig.  115  is 
shown  the  crossing  of  two  western  lines  where  special  cross- 
arming  was  fitted  to  a  standard  tower  of  the  line  first  built. 

Corner  towers  as  ordinarily  used  for  angles  encountered  in 
transmission  work  are  hardly  what  would  be  called  special  struc- 
tures, being  generally  of  the  same  design  as  the  line  towers  except 
that  they  are  heavier  and  in  the  case  of  pin-type  insulators, 
arranged  for  the  use  of  two  or  more  insulators  per  conductor; 
it  is  only  where  extraordinary  conditions  are  met  with  that  other 
designs  are  called  for. 

Figures  116,  117  and  118  show  typical  standard  angle  towers, 
the  first-mentioned  being  the  "Aermotor"  tower  used  for  the 
140,000-volt  construction  of  the  Au  Sable  Electric  Company,  and 
the  other  two  being  respectively  the  small  angle  and  the  regular 
corner  arrangement  on  the  Ontario  Hydro-Electric  Power  Com- 
mission system.  Fig.  119  shows  an  Archbold-Brady  special 
corner  structure  used  on  the  transmission  line  for  the  Hoosac 
Tunnel  electrification  of  the  Boston  &  Maine  Railroad. 


CHAPTER  IX 
CROSS-ARMS,  HARDWARE,  PINS  AND  INSULATORS 

Cross-arms  as  used  in  wooden  pole  line  work  are  usually  long- 
leaf  yellow  pine,  Washington  fir,  short-leaf  yellow  pine  or  Norway 
pine,  though  other  woods,  such  as  oak,  spruce,  cedar,  white  pine 
and  cypress,  have  also  been  used  to  a  limited  extent;  in  some  few 
instances  steel,  naturally  almost  always  used  in  steel  pole,  steel 
tower  or  concrete  pole  work,  has  been  employed  in  wooden  pole 
construction,  angle  sections  being  used  in  most  cases. 

For  transmission  line  work  exceeding  about  5000  volts,  there 
is  no  standard  size  of  cross-arms,  but  for  light  construction  in 
voltages  up  to  22,000  volts  or  so,  a  regular  electric  light  arm  of  the 
pin  size  required  to  give  adequate  conductor  spacing,  has  often 
been  used;  the  section  of  standard  electric  light  arms,  31/4  in.  X 
4  1/4  in.,  is  heavy  enough  for  this  class  of  work  as  a  usual  thing. 
In  the  heavier  construction  at  the  higher  voltages,  almost  every 
individual  line  builder  has  had  his  own  ideas  as  to  the  most 
suitable  proportions  for  the  section  of  wooden  arms,  and  we  find 
them  4  in.  X  5  in.,  4  in.  X  6  in.,  5  in.  X  6  in.,  5  in.  X  7  in.,  and  in 
all  the  possible  fractional  combinations  intermediate;  the  con- 
ductor spacing  demanded  by  the  voltage,  and  the  size  and 
number  of  the  line  wires,  naturally  determine  the  length  and 
section  of  a  cross-arm,  but  in  the  case  of  lines  built  under  iden- 
tical conditions,  great  variations  in  this  feature,  especially  as  to 
the  section  of  the  arms,  are  often  noted. 

Long-leaf  yellow  pine  and  Washington  fir  are  the  most  favored 
of  all  timbers  for  high-class  construction,  being  of  good  strength 
and  moderate  weight,  and  possessing  good  lasting  qualities;  the 
National  Electric  Light  Association  gives  the  average  life  of 
pine  as  8.7  years,  and  that  of  fir  as  11.0  years,  for  untreated  arms. 

In  the  past  no  attempt  was  made  to  protect  arms  against 
deterioration  except  by  the  application  of  a  coat  of  mineral  paint, 
which  applied  to  unseasoned  woods  in  most  cases  was  worse  than 
nothing  at  all.  In  the  last  few  years  with  the  attention  given  to 
increasing  the  useful  life  of  the  poles,  the  preservation  of  cross- 

184 


CROSS-ARMS,  HARDWARE,  AND  PINS          185 

arms  against  decay  has  been' given  serious  consideration,  and  they 
are  now  frequently  subjected  to  treatments  by  the  same  processes 
as  the  poles.  Many  companies,  however,  that  do  butt-treat 
their  poles  do  not  use  treated  arms,  figuring  that  the  ex- 
pense is  not  warranted  and  that  if  arms  are  carefully  seasoned 
under  cover  for  six  months  or  a  year  and  then  given  a  good  coat 
of  mineral  paint,  the  resultant  life  is  more  economical  than  that 
of  a  treated  arm.  There  are  many  localities,  however,  where  the 
climatic  conditions  do  make  the  preservation  of  cross-arms  an 
economical  matter  and  in  such  places  creosoted  or  kyanized  arms 
have  been  employed  with  satisfactory  results.  Forest  Service 
Bulletin  No.  151  gives  interesting  details  of  government  investi- 
gations of  the  application  of  creosote  to  cross-arms  by  the  pressure 
process.  The  cost  of  creosoting  will  run  from  2  cents  to  3  cents 
per  foot  board  measure.  The  Government  recommends  an 
absorption  of  about  6  Ib.  of  oil  per  cubic  foot  for  Class  A  timber 
(75  per  cent,  or  over  heart-wood),  10  Ib.  per  cubic  foot  for  Class  B 
(75  per  cent,  or  over  sap-wood),  and  8  Ib.  per  cubic  foot  for 
Class  C,  intermediate  between  A  and  B.  Arms  of  the  above 
classes  should  be  treated  separately  and  all  timber  should  pref- 
erably be  held  until  it  is  in  an  air-dry  condition  before  being 
treated. 

Cross-arm  timber  should  be  first-class,  sound,  live,  straight- 
grained  and  free  from  pine  knots,  pitch,  seams,  splits  or  shakes; 
knots  3/4  in.  or  less  in  diameter  may  and  usually  are  allowed  if 
they  are  solid  and  do  not  reduce  the  strength  of  the  arm  to  any 
appreciable  extent.  The  arms  should  be  surfaced  four  sides  with 
a  3/8-in.  or  1/2-in.  bevel  along  the  top  edges  and  all  holes  should 
be  bored  clean  and  to  dimension.  In  some  cases  the  tops  of  arms 
have  been  rounded  off,  but  with  the  type  of  pins  now  generally 
used  in  high-tension  work,  a  flat-topped  arm  is  required. 

The  prices  of  cross-arms  vary  somewhat  with  the  market,  and 
with  the  length  and  boring  called  for,  but  the  following  prices  are 
representative  for  long-leaf  yellow  pine  arms  delivered  in  the 
Middle  West  in  1911-12: 

3i  in.  X4±  in.,  per  lineal  foot $0.0375 

4    in.  X4    in.,  per  lineal  foot 055 

4    in.X5    in.,  per  lineal  foot 075 

4  in.  X6    in.,  per  lineal  foot 0825 

4£  in.  X5|  in.,  per  lineal  foot 089 

5  in.  X7    in.,  per  lineal  foot 12 


186  TRANSMISSION  LINE  CONSTRUCTION 

Fir  cross-arms  will  run  from  5  per  cent,  to  15  per  cent,  higher 
in  price  than  the  yellow  pine. 

Steel  cross-arms  are  seldom  used  in  straight  wooden  pole  con- 
struction except  where  some  unusual  arrangement  of  the  pole  top, 
such  as  that  shown  in  Fig.  9  in  Chapter  III,  is  followed;  the  angle- 
iron  section  is  the  one  that  is  generally  employed,  of  the  dimension 
and  unit  weight  demanded  by  conditions;  the  channel  section 
has  been  used  a  little.  Generally  steel  arms  have  been  employed 
painted,  and  the  cost  of  them  drilled  complete  and  with  one 
shop  coat,  runs  from  21/2  cents  to  3  cents  per  pound.  The  use 
of  reinforced  concrete  cross-arms  in  connection  with  concrete  poles 
has  been  suggested  and  experimented  with,  but  to  the  best 
knowledge  of  the  writer,  has  not  been  given  a  commercial  test; 
the  cross-arming  of  concrete  poles  is  generally  of  steel,  though 
wood  has  been  used  quite  a  bit  also. 

Cross-arms  should  in  all  cases  be  snugly  fitted  into  a  3/4-in. 
gain  and  attached  to  the  pole  by  means  of  a  single  through 
bolt,  usually  3/4  in.  or  7/8  in.  in  diameter,  2  1/4-in.  X2  1/4-in.  X 
3/16-in.  or  3-in.  x3-in.  X  1/4-in.  washers  being  used  under  the 
head  and  nut;  through  bolts,  with  nuts  and  washers,  should  be 
galvanized,  preferably  by  the  sherardizing  process,  after  all 
threading  is  completed.  In  purchasing  through  bolts,  they 
should  be  specified  to  have  a  3-in.  or  4-in.  length  of  threading, 
with  the  threads  rolled. 

Cross-arm  braces  may  be  either  flat-bar  or  light  angle  iron; 
in  transmission  line  work,  the  flat-bar  braces,  one  to  each  side  of 
the  arm,  are  generally  used,  though  in  many  installations  only 
one  side  of  the  arm  has  been  braced;  in  many  of  the  older  lines 
and  in  some  quite  recent  ones  where  two-pole  fixtures  have  been 
used,  oak  or  maple. braces  have  been  employed.  The  standard 
section  of  steel-bar  braces  is  1/4  in.Xl  1/4  in.  with  lengths 
running  from  20  in.  to  32  in.;  for  transmission  work  these  braces 
are  often  not  considered  heavy  enough  and  larger  section  bars 
are  specified,  depending  upon  the  length  of  the  arms  and  the 
size  of  the  conductors.  Braces  of  this  type  are  through-bolted 
to  the  cross-arm  with  a  1/2-in.  carriage  bolt  usually,  and  are 
attached  to  the  pole  with  5/8-in.  x6-in.  or  7-in.  lag  screws;  the 
pole  ends  of  braces  are  sometimes  fastened  with  a  through  bolt 
in  place  of  a  lag,  and  a  machine  bolt  instead  of  a  carriage  bolt, 
used  for  the  cross-arm  end;  where  a  machine  bolt  is  employed 
to  attach  the  brace  to  the  cross-arm,  it  is  possible  to  drive  the 


CROSS-ARMS,  HARDWARE,  AND  PINS          187 

bolt  through  the  arm  from  the  brace  side  so  that  should  the 
nut  work  off,  the  bolt  will  tend  to  hold  the  brace  in  position 
whereas  if  the  nut  be  on  the  brace  side  and  drops  off,  there  is 
nothing  but  the  short  protruding  length  of  bolt  to  depend  upon; 
the  use  of  a  machine  bolt  at  the  arm  end  of  a  brace  is  therefore 
preferable,  but  in  the  writer's  experience  nothing  is  gained  by 
substituting  a  through  bolt  for  a  lag  bolt  at  the  pole  end. 

Where  a  lag  bolt  is  used  for  the  heel  or  toe  bolt,  as  the  pole 
fastening  of  a  brace  is  termed,  it  is  often  specified  that  it  shall 
be  driven  in  for  not  more  than  1  in.  and  turned  in  with  a  wrench 
the  rest  of  the  way;  common  practice,  however,  is  to  drive  heel 
bolts  in  for  about  the  length  of  the  thread  and  turn  them  in  the 


FIG.   120. — Angle  iron  cross-arm  brace. 

balance  of  their  length,  and  the  writer  has  never  found  anything 
to  indicate  unsatisfactory  results  from  this  method.  A  washer 
should  be  used  under  the  head  of  the  heel  bolt  to  assist  in  setting 
it  up  tight. 

Angle-iron  braces  in  one  piece,  as  shown  in  Fig.  120,  have 
been  used  to  some  extent  in  wooden  pole  work,  but  their  cost  is 
necessarily  higher;  the  section  of  the  angle  is  usually  11/2  in.  X 
1  1/2  in.x3/16  in.  or  1  3/4  in.  X  1  3/4  in.x3/16  in.  As  will  be 
noted  from  the  illustration  these  braces  are  fitted  to  the  bottom 
of  the  arm  instead  of  the  side  as  with  the  flat-bar  type. 

All  pole  hardware  should  be  galvanized,  excepting  possibly  the 
heel  bolt,  and  as  noted  previously,  the  threads  should  be  rolled, 
and  all  operations  concluded  before  galvanizing  is  done,  so  that 
the  entire  surface  will  be  protected. 

Bolts,  lags,  braces  and  washers  should  be  shipped  in  unit 
packages  and  bundles,  the  bolts  and  washers  in  kegs,  stenciled 


188  TRANSMISSION  LINE  CONSTRUCTION 

with  number  contained  and  size,  and  the  braces  in  bundles  well 
wired  together  and  tagged;  as  a  usual  thing  braces  come  in 
bundles  of  twenty  making  a  convenient  weight  and  size  to 
handle.  All  hardware  should  be  stored  under  cover  as  it  comes 
in;  and  if  possible,  for  obvious  reasons,  under  lock  and  key;  the 
material  should  be  arranged  systematically  by  size  so  that  there 
need  be  no  confusion  in  loading  up  for  distribution  and  so  that 
the  stock  on  hand  at  any  time  can  be  readily  checked. 

As  cross-arms  come  in,  usually  in  box  cars,  they  should  be 
piled  on  blocking  or  skids  clear  of  the  ground,  in  a  place  con- 
venient for  the  loading  of  teams,  and  if  they  are  to  be  held  for  any 
length  of  time,  in  such  a  manner  that  there  will  be  as  free  air 
circulation  through  the  pile  as  possible.  To  allow  for  checking 
over  of  stock,  they  should  be  arranged  systematically  in  piles  of 
a  certain  number. 

The  distribution  of  cross-arms,  braces  and  bolts  is  usually 
carried  on  just  in  advance  of  the  setting  work,  though  some- 
times where  poles  are  set  without  arms,  the  work  coincides  with 
the  distribution  of  insulators:  In  distributing  arms  and  hard- 
ware, teams  should  be  loaded  up  with  the  requisite  amount  of 
material  for  a  certain  stretch  of  poles  and  the  teamster  directed 
to  begin  distributing  at  a  certain  number  stake  and  leave  one 
complete  set  of  fittings,  as  per  a  standard  list  provided  him,  at 
each  pole  location  from  there  on  to  the  end  of  the  stretch  covered 
by  his  load,  except  at  such  locations  as  are  otherwise  specified  on 
his  slip.  The  work  of  distribution  is  often  directed  by  the  foreman 
of  the  crew  in  the  field  but  the  better  way  is  to  place  the  re- 
sponsibility for  distributing  and  keeping  record  of  all  material 
in  the  hands  of  a  stock  or  material  man,  as  discussed  in  Chapter 
XIII.  Braces  should  be  bolted  to  the  arms  before  loading  for 
distribution,  and  in  the  case  of  certain  types  of  pins,  they  may 
also  be  fitted  in  the  yard,  which  can  be  done  usually  by  the 
material  man  in  between  times;  it  is  well,  especially  in  the 
winter  time,  to  require  that  the  arms  shall  be  set  leaning  up 
against  the  pole  with  the  bolts  laid  on  top;  washers  should  be 
slipped  on  the  bolts;  material  should  preferably  be  hauled  out 
only  sufficient  for  each  day's  progress. 

Insulator  pins  for  wooden  construction  should  preferably  be 
iron,  though  for  the  lower  voltages,  up  to  20,000  volts  or  better, 
wooden  pins  are  much  employed;  in  older  construction  wooden 
pins  have  been  used  for  potentials  up  to  60,000  or  70,000  volts. 


CROSS-ARMS,  HARDWARE,  AND  PINS          189 

The  objections  to  wooden  pins  are  both  mechanical  and  electrical, 
and  naturally  are  most  apparent  in  the  higher  voltages  where 
taller  insulators  are  required  and  where  the  electrical  conditions 
are  more'  severe.  Wooden  pins  are  weaker  than  steel  and  being 
of  greater  diameter  require  a  larger  hole  in  the  arm,  not  only 
weakening  it  from  the  start,  but  offering  a  greater  opportunity 
for  decay;  then  for  voltages  above  25,000  volts  to  30,000  volts 
under  certain  climatic  conditions,  and  above  50,000  volts  gener- 
ally, the  digesting  or  carbonizing  of  wooden  pins  from  leakage  is 
a  serious  drawback  to  their  use. 

Locust,  oak  and  maple  have  been  the  most  extensively  used 
pin  timbers;  as  a  rule  pins  outlast  the  arms,  having  an  average 
life  of  eleven  years,  according  to  the  National  Electric  Light 
Association,  unless  conditions  are  such  that  they  are  subject  to 
digestion. 

Wooden  pins  are  made  with  the  shank  or  part  fitting  into  the 
cross-arm  slightly  tapered,  and  the  holes  in  the  arms  should  be 
bored  so  that  the  pin  will  fit  snugly  when  driven  in;  in  low-'tension 
work,  the  pins  are  then  set  up  by  driving  a  six-penny  nail  through 
the  arm  and  pin,  and  in  higher  voltage  work,  by  means  of  a 
3/8-in.  through  bolt  passing  through  the  arm  and  pin.  Inmost 
cases  where  wooden  pins  have  been  used  in  high-tension  work, 
they  have  been  either  creosoted  or  boiled  in  linseed  oil  or  paraf- 
fine;  the  method  of  treating  pins  with  paraffine  is  akin  to  the 
open  tank  process  for  the  impregnation  of  timber  with  creosote, 
described  in  Chapter  IV.  They  are  placed  in  a  tank  of  hot 
paraffine,  maintained  at  as  high  a  temperature  as  practicable 
without  danger  of  flashing,  and  kept  there  for  four  to  six  hours, 
after  which  the  bath  is  allowed  to  cool;  after  the  paraffine  has 
solidified,  the  pins  are  removed  by  reheating  the  tank  until  the 
wax  is  fluid. 

The  timber  for  pins  should  be  sound,  live,  straight-grained, 
and  generally  free  from  sap-wood,  knots  and  checks,  with  the 
grain  running  fairly  true  with  the  axis  of  the  pin;  small  solid, 
sound  knots,  not  more  than  1/4  in.  in  diameter,  are  permissible 
as  well  as  a  small  amount  of  sap-wood,  if  they  be  above  the 
shoulder  of  the  pin.  Pins  should  be  seasoned  thoroughly  before 
being  turned,  should  be  close  to  the  dimensions  called  for, 
should  have  clean-cut  uniform  threads  and  a  reasonably  smooth 
finish. 

Iron  pins,   as  they  are  generally  classed,   may  be   of  steel, 


190 


TRANSMISSION  LINE  CONSTRUCTION 


malleable  iron,  cast  iron  or  cast  steel,  or  combinations  of  two 
of  them. 

The  earlier  type  of  iron  pins  was  an  adaptation  of  the  forms 
of  wooden  pins,  extra  heavy  pipe,  usually  2-in.,  being  swaged 


FIG.  121. — Ridge  pin. 


o 


o 


FIG.  122  (a,  b,  c.) — Pole  top  pins. 


to  fit  and  be  cemented  into  the  insulators,  the  whole  being- 
mounted  on  the  cross-arm  in  the  same  manner  as  a  wooden 
pin;  made  a  little  longer  with  the  shank  flattened  and  drilled 
with  two  holes  for  through  bolts,  or  with  a  regular  pin  mounted 
in  the  manner  illustrated  in  Fig.  5,  Chapter  III,  this  type  of 


CROSS-ARMS,  HARDWARE,  AND  PINS          191 

pin  was  adapted  for  use  at  the  top  of  a  pole,  and  was  a  great 
improvement  over  the  method  previously  followed,  of  setting 
the  top  pin  into  a  hole  bored  into  the  pole  roof,  not  only  making 
a  better  job  mechanically,  but  lessening  the  danger  of  rot. 
With  the  beginning  of  the  use  of  metal  pins,  and  with  the 
development  of  porcelain  insulators,  better  designs  of  pins  were 
worked  out  and  now  for  low-tension  work,  that  is  for  potentials 
up  to  about  25,000  volts,  either  a  ridge  pin  such  as  is  shown  in 
Fig.  121,  or  a  malleable  pole-top  pin  such  as  is  illustrated  in 
Fig.  122,  6  or  c,  is  used,  while  for  the  higher  voltages  the  type 
with  separable  thimble,  shown  in  Fig.  122,  a,  is  generally  employed. 
Fig.  122,  c,  is  the  same  as  122,  b,  except  that  the  former  is  pro- 
vided with  a  threaded  lead  thimble,  cast  on  the  end,  whereas 
the  latter  is  cemented  into  the  insulator.  With  the  separable 
type  of  pin,  the  thimble  is  usually  cemented  into  the  insulator 
at  the  factory. 


FIG.  123. — Cross-arm  pin. 

For  cross-arm  work  the  defect  of  a  pin  requiring  a  large  hole 
in  the  cross-arm  was  early  realized,  and  pins  of  the  type  shown 
in  Fig.  123  were  offered,  consisting  of  a  cast-iron  base  cemented 
into  the  insulator,  and  held  to  the  arm  by  a  stud  bolt  screwed 
into  the  base.  Cemented  into  an  insulator,  this  latter  type 
of  pin  was  hard  to  install  on  a  pole  in  the  larger  sizes,  especially 
where  an  insulator  was  to  be  replaced  in  a  hurry,  and  on  this 
account  and  also  to  avoid  the  necessity  of  carrying  a  heavy 
cemented  unit,  a  lead  thimble,  cast  on  the  end  and  threaded, 
is  preferable.  This  gives  the  installation  flexibility  of  a  wooden 
pin,  and  in  medium  voltages  works  out  quite  well. 

For  general  transmission  line  work,  however,  pins  with  separa- 
ble thimbles,  such  as  are  illustrated  in  Figs.  124  and  125,  are 
the  best;  in  these  a  threaded  cast-iron  thimble  is  cemented 
into  the  insulator  pin  hole,  preferably  at  the  insulator  factory, 
and  the  balance  of  the  pin  installed  permanently  on  the  arm, 
the  insulators  being  readily  placed  in  position  or  changed  by 


192 


TRANSMISSION  LINE  CONSTRUCTION 


screwing  on,  or  unscrewing  the  thimble,  to  or  from  the  pro- 
jecting end  of  the  stud  "bolt.  In  Fig.  124,  it  will  be  noted  that 
the  base  is  itself  threaded  at  the  top  and  that  the  pin  bolt  is 


FIG.   124. — Separable  type  cross-arm  pin. 

screwed  through  the  threaded  neck  so  as  to  project  the  required 
distance  above  the  top  of  the  cone  casting;  in  Fig.  125,  a  flat 
nut  is  used  in  place  of  a  threaded  section  in  the  base,  and  this 


FIG.  125. — Separable  type  cross-arm  pin. 

is  turned  down  into  position  and  the  base  slipped  on,  or  vice 
versa.  When  the  separable  top  pin  was  first  introduced,  there 
was  no  way  of  installing  them  on  a  cross-arm  without  an  insula- 
tor in  place,  the  use  of  threading  at  the  neck  of  the  base  or  of 


CROSS-ARMS,  HARDWARE,  AND  PINS          193 

a  nut,  not  having  been  developed.  This  pin  bolt  was  therefore 
screwed  into  the  insulator  thimble  and  the  base  slipped  over 
the  pin,  the  whole  then  being  held  and  the  end  of  the  bolt  intro- 
duced in  the  hole  in  the  arm;  where  66,000-volt  insulators, 
weighing  about  35  Ib.  with  pins  weighing  12  Ib.  to  15  Ib.,  were  to 
be  installed  in  wooden  pole  work,  this  type  of  pin  was  not 
exactly  a  thing  of  joy  for  the  linemen. 

Besides  the  all-metal  pin  for  the  range  of  voltages,  we  have 
porcelain  base  pins  with  lead  or  wood  thimbles  and  steel  pin 
bolts,  which  require  no  cementing,  the  insulator  pin  hole  being 
threaded  as  with  plain  wooden  pins;  and  for  the  lower  voltages, 
we  have  a  wooden-base  pin  with  a  steel  through  bolt. 

In  general  for  pins  we  may  say  that  an  all-metal  pin  should 
be  used  always  in  steel  construction,  and  in  wooden  pole  work 
for  potentials  above  44,000  volts;  below  this  pressure,  a  porcelain 
base  pin  may  be  used,  though  an  all-metal  pin  is  preferable 
for  all  voltages  exceeding  about  22,000  volts;  an  all-wooden 
pin  should  not  be  used  for  pressures  above  22,000  volts  for  first- 
class  line  construction.  Where  metal  pins  or  part  metal  pins  are 
used,  these  should  be  galvanized  throughout  and,  for  potentials 
higher  than  about  44,000  volts,  the  pins  should  preferably  be 
of  the  separable  type,  arranged  for  permanent  installation  on 
the  arms. 

For  the  insulation  of  transmission  lines  we  have  offered, 
porcelain,  glass,  and  patented  compounds. 

The  proprietary  compounds  possess  very  good  mechanical 
characteristics  and  excel  porcelain  or  glass  in  this  regard,  but  it 
is  doubtful  if  any  insulator  of  this  kind  of  material  can  for  any 
length  of  time  withstand  the  ravages  of  weather,  combined 
with  the  electric  strains  obtaining  in  high-voltage  work;  insula- 
tors of  this  type  have  not  as  yet  been  used  commercially  to 
any  great  extent. 

Glass  is  the  oldest  commercial  insulating  material  for  line 
work  and  possesses  good  insulating  qualities,  is  cheap,  and 
allows  the  detection  of  flaws,  etc.,  by  visual  inspection,  but  is 
mechanically  weak,  and  subject  to  surface  deterioration;  glass 
insulators  of  any  size  will  often  fail  from  unequal  temperature 
strains  alone. 

Porcelain  with  its  superior  mechanical  strength  and  its 
dialectric  strength,  though  of  greater  cost  than  glass,  is,  even 
in  the  very  low  voltages,  accordingly  used  generally  as  the 

13 


194  TRANSMISSION  LINE  CONSTRUCTION 

material  for  insulators.  Porcelain,  for  insulator  purposes, 
should  have  a  fine  uniform  grain,  free  from  blow-holes,  cracks 
or  strata;  an  insulator  broken,  should  show  a  clean  even  fracture 
and  the  fractured  surface  should  be  neither  chalky  nor  too 
glossy,  the  former  indicating  under-  and  the  latter,  overfiring; 
drops  of  red  ink  placed  upon  the  fractured  surface  should  not 
spread  nor  be  absorbed.  Exposed  surfaces  of  an  insulator 
should  be  evenly  glazed,  preferably  a  brown  color,  and  should 
be  smooth  and  glossy,  without  pits,  ridges,  hollows  or  anything 
that  will  catch  and  retain  dirt;  the  glazing  should  show  no 
crazing  or  hair  cracks.  It  is  very  probable  that  a  great  many 
insulator  failures  have  been  due  to  a  combination  of  underfired 
porcelain  and  crazed  glazing,  and  that  what  has  been  termed 
fatigue  of  insulators  is  merely  the  depreciation  of  the  insulation 
through  absorption  of  moisture  in  such  cases. 

For  the  support  of  conductors  we  have  two  distinct  types  of 
insulators  in  the  pin  and  the  suspension  designs,  the  former 
being  made  for  all  voltages  up  to  88,000  volts,  and  the  latter  in 
units  rated  at  11,000  volts  to  25,000  volts,  the  number  of  units 
required  depending  upon  the  line  voltage.  The  unit  type  of 
insulator  is  finding  great  favor  for  all  voltages  above  33,000  volts, 
but  for  pressures  up  to  50,000  volts  or  60,000  volts  the  pin  type 
is  still  holding  its  own. 

In  America  the  pin-type  insulators  for  the  higher  voltages  are 
made  up  of  three  or  four  parts  cemented  together  with  neat 
Portland  cement,  the  same  being  preferably  done  at  the  factory, 
but  sometimes  carried  on  in  the  field;  medium  voltage  insulators 
are  made  up  in  two  parts. 

In  the  selection  of  an  insulator  of  the  pin  type  to  operate 
under  a  certain  pressure,  consideration  must  be  given  not  only  to 
the  internal  electrical  conditions  of  the  system,  but  also  to  the 
mechanical  features  involved,  and  to  the  climatic  conditions  met 
with,  such  as  the  prevalence  of  dust  and  salt  storms,  fogs  and 
long  rainy  seasons,  heavy  lightning  storms,  etc.  The  design  of 
an  insulator  is  not  usually  within  the  province  of  a  transmission 
line  engineer  or  at  least  should  not  be;  while  experience  will 
teach  him  undesirable  features,  it  requires  long  and  careful 
experimental  work  to  determine  those  that  will  give  the  most 
economical  and  efficient  designs,  and  it  is  usually  best  to  specify 
performance,  and  rely  upon  the  designs  submitted  by  well- 
known  manufacturers. 


CROSS-ARMS,  HARDWARE,  AND  PINS          195 

Specifications  for  pin-type  insulators  should  in  addition  to  the 
quality  of  the  material  and  details  of  finish,  etc.,  list  the  tests  for 
performance  and  specify  in  detail  the  manner  of  applying  them; 
generally  a  dry  flash-over  test  of  from  two  and  one-half  to  three 
times  the  rated  line  voltage,  and  a  wet  flash-over  of  at  least 
one  and  one-half  to  two  times  the  rated  line  voltage,  are  called 
for,  depending  upon  the  line  conditions;  a  puncture  test  at  the 
full,  or  at  least  75  per  cent,  of  the  full,  rated  line  voltage,  applied 
to  any  shell  separately,  is  also  usually  specified.,  Doctor  Stein- 
metz  has  suggested  that  specifications  for  insulators  also  call  for 
a  series  of  electrical  tests  to  be  made  upon  samples  that  have  been 
immersed  in  water  for  a  week  or  ten  days;  this  kind  of  a  test  will 
assist  in  weeding  out  the  kind  of  insulators  that  might  be  sub- 
ject to  "fatigue"  later  on,  as  previously  noted. 

While  in  this  country  the  practice  has  been  to  design  insulators 
with  multiple  parts  to  secure  the  required  leakage  distance,  the 
same  result  is  obtained  in  Europe  by  molding  petticoats  on  the 


i 
FIG.  126a,  b,  c. — Typical  European  pin-type  insulators. 

shells  and  using  probably  two-part  designs  where  we  use  three 
or  four.  One-piece  insulators  up  to  12  in.  in  diameter,  of  the 
design  shown  in  Fig.  126,  a,  have  been  successfully  manufactured 
in  Germany.  Figs.  126,  b  and  c,  show  two  other  typical  German 
insulators  of  the  pin  type.  For  a  study  of  European  insulators 
the  reader  is  referred  to  a  series  of  papers  in  the  Elektrotechnische 
Zeitschrift  for  Jan.  13,  20,  and  27,  1910;  also  in  the  Electrical 
World  for  May  19,  1910,  A.  S.  Watts  gives  an  interesting  compari- 
son of  American  and  European  insulator  designs. 

In  Figs.  127,  128,  129, 130  and  131  are  shown  typical  designs  of 
American  pin-type  insulators  for,  respectively,  13,000,  23,000, 
35,000,  44,000  and  66,000  volts.  The  cost  of  pin-type  insulators 


196 


TRANSMISSION  LINE  CONSTRUCTION 


for  a  certain  voltage  varies  of  course  with  the  factor  of  safety 
called  for;  for  pressures  up  to  and  including  33;000  volts,  a 
factor  of  safety  of  3  for  dry  flash-over  and  2  for  wet  test 


FIG.  127. — 13,000-volt  insulator. 


FIG.  128.— 23,000-volt  insulator. 

can  be  readily  secured,  but  above  that  point,  insulators  with 
those  rated  safety  factors  will  be  expensive. 

Pin-type  insulators  above  66,000  volts  are  very  heavy  and  ex- 
pensive and  on  account  of  the  height  of  pin  required  subject 


CROSS-ARMS,  HARDWARE,  AND  PINS          197 


FIG.  129. — 35,000-volt  insulator.  . 


FIG.  130. — 44,000-volt  insulator. 


198 


TRANSMISSION  LINE  CONSTRUCTION 


the  cross-arms  to  a  heavy  torsional  strain.  The  cost  of  securing 
a  suitable  safety  factor  together  with  the  mechanical  considera- 
tions involved  led  the  insulator  manufacturers  to  seek  new 
methods. 

With  the  reincarnation  of  the  suspension-type  insulator,  used 
in  the  early  days  of  telegraph  line  construction  and  abandoned  on 
account  of  its  clearance  requirements,  the  problem  of  insulating 
lines  for  pressures  above  60,000  volts  or  70,000  volts,  and  espe- 
cially above  100,000  volts,'  was  greatly  simplified.  So  rapidly 
has  the  suspension  insulator  come  into  favor,  that  it  is  being  used 
in  many  instances  where  economical  considerations  would  tend 
to  prove  the  pin  type  preferable. 


FIG.  131. — 66,000- volt  insulator. 

The  advantage  of  a  suspension-type  insulator  over  a  pin  type 
lies  in  the  fact  that  it  is  electrically  more  efficient  and  mechanic- 
ally stronger,  not  only  in  itself  but  in  the  lesser  strain  that  it  exerts 
upon  the  cross-arms,  and  commercially  a  better  business  proposi- 
tion in  that  the  voltage  of  transmission  can  be  raised  by  the  addi- 
tion of  extra  units  without  scrapping  or  sacrificing  the  former 
insulators,  as  would  be  the  case  with  the  pin  type.  Again  in  the 
case  of  an  insulator  failure,  where  multiple  units  are  used,  the 
damage  is  usually  confined  to  one  unit,  which  can  be  replaced  at 
a  correspondingly  low  cost. 

The  specifications  for  suspension-type  insulators  are  the  same 
as  for  the  pin  type  as  far  as  workmanship  and  material  are  con- 


CROSS-ARMS,  HARDWARE,  AND  PINS          199 

cerned,  but  in  specifying  performance,  tests  not  only  of  separate 
units  should  be  called  for,  but  dry  and  wet  flash-over  tests  of  the 
standard  string  of  units,  with  regular  interconnection  and  spacing 
between  them,  and  with  a  stated  mechanical  load  applied,  should 


FIG.   132. — Two  part  cemented  suspension  type  unit. 

be  made.  Recent  tests  of  series  of  units  under  both  wet  and 
dry  conditions  demonstrate  that  the  effective  voltage  per  unit 
drops  off  very  fast  as  the  number, of  units  is  increased,  and  the 
assembled  tests  under  line  conditions  should  be  made  to  deter- 


FIG.  133. — Two  part  cemented  suspension  type  unit. 

mine  the  actual  safety  factor.  The  units  in  series  also  do  not 
carry  the  same  insulation  "load,"  the  one  connected  to  the  line 
being  under  greater  voltage  strain  than  the  one  farther  along, 
and  the  second  under  greater  strain  than  the  third  and  so  on; 


200 


TRANSMISSION  LINE  CONSTRUCTION 


when  a  long  series  of  units  is  to  be  used  it  appears  that  some 
means  of  lowering  this  potential  gradient  either  by  spacing  or 
by  a  variation  in  the  dimension  of  the  units  can  be  worked 
out  so  as  to  increase  the  assembled  working  pressure  of  the 
series,  though  the  practicability  of  any  such  arrangement  is 
questionable. 

Different  designs  of  suspension-type  insulators  are  offered  by 
the  various  insulator  manufacturing  companies,  some  a  two- 
part  cemented  unit  as  illustrated  in  Figs.  132  and  133,  others  a 


FIG.   134. — One  piece  suspension  type  unit. 

one-piece  cemented  unit  as  shown  in  Fig.  134,  and  still  others  of 
the  all-porcelain  interlinking  type  shown  in  Fig.  135.  There 
has  been  some  discussion  as  to  the  relative  constructional  merits 
of  the  cemented  and  the  interlinking  types,  many  engineers 
having  favored  the  latter  because  of  the  mechanical  inter- 
connecting feature  between  units,  in  the  event  of  the  shattering 
of  the  porcelain  body,  and  the  argument  advanced  by  adherents 
of  the  cemented  type  has  been  that  the  connections  of  a  broken 
unit  would  not  as  a  general  thing  be  pulled  into  good  contact 
and  often  into  no  contact  at  all  so  that  *the  arc  between  the 


CROSS-ARMS,  HARDWARE,  AND  PINS          201 

interlinking  parts  would  destroy  the  loops  and  drop  the  wire. 
The  point  has  also  been  advanced,  that  with  the  type  of  inter- 
connection used  for  the  cemented  type  it  is  possible  to  subject 
every  unit  to  mechanical  test,  while  with  the  interlinking  designs, 
the  strength  of  the  series  depends  upon  the  care  exercised  in  the 
erection  work.  In  repair  work,  the  replacing  of  a  unit  of  the 
cemented  type  can  be  effected  more  easily  and  quickly  than 
that  of  an  interlinking  type;  also  where  a  long  series  of  units 


FIG.   135. — Interlinking  type  suspension  unit. 


is  used  for  the  higher-voltage  work,  the  possibility  of  maintaining 
a  more  closely  uniform  spacing  between  units  as  desired,  is 
a  great  point  in  favor  of  the  cemented  type. 

There  has  been  much  important  work  where  each  type  of 
insulator  has  been  employed,  but  as  a  rule  it  appears  that 
engineers  favor  the  cemented  type;  between  the  relative  merits 
of  the  one-piece  and  the  two-piece  cemented  types  there  is 
much  discussion,  the  question  being  whether  it  is  better  to  use, 
say  for  100,000- volt  service,  four  units  of  the  larger  diameter 


202 


TRANSMISSION  LINE  CONSTRUCTION 


two-piece  type,  or  six  units  of  the  smaller  diameter  one-piece 
design.  The  following  comparison  of  the  two  types,  each  with 
units  for  100,000-volt  line  pressure,  as  made  by  A.  O.  Austin 
in  his  paper  before  the  1911  convention  of  the  American  Institute 
of  Electrical  Engineers,  gives  a  concise  summary  of  their  respective 
merits,  as  well  as  interesting  information  as  to  details  of  insula- 
tors for  100,000-volt  service. 


One-piece 

type 

Two-piece 
type 

Number  of  sections  

6 

4 

Number  of  shells  per  section 

1 

2 

Diameter  

10  in 

14^  in 

Length  of  insulator  

34£  in. 

41  in. 

Mechanical  strength  

10,000  Ib. 

8,000  Ib. 

Weight  of  porcelain  

30  Ib. 

62  Ib. 

Total  weight  

50  Ib 

90  Ib. 

Number  of  cemented  joints  

12 

12 

Formation  of  arc  —  dry  

Through  air 

Over  surface 

Formation  of  arc  —  wet  

Through  air 

Over  surface 

Total  tested  dialectric  strength  

540  kv. 

440  kv. 

Wet  flash-over  

265  kv. 

235  kv. 

Depreciation  due  to  loss  of  one  section  .... 

16§  per  cent. 

25  per  cent. 

In  passing,  the  factors  of  safety  shown  in  the  above  com- 
parative tests  will  be  noted  as  being  far  greater  than  those  of  the 
pin  type  as  generally  rated. 

In  Europe  the  development  of  the  suspension-type  insulator 
has  been  along  the  same  lines  generally  as  in  this  country;  they 
have,  however,  been  of  the  one-piece  type  with  turned  petticoats 
on  the  same  order  as  the  pin-type  designs  previously  commented 
on;  they  have  been  made  both  with  cemented  and  interlinked  con- 
nections. Figs.  136  and  137,  a,  6,  show  the  insulators  used  for 
the  Lauckhammer  110,000-volt  work,  see  Figs.  46  and  47, 
the  suspension  unit  in  Fig.  136  being  used  five  in  series  and  the 
regular  strain  insulator,  Fig.  137,  a,  six  in  a  string;  the  design 
shown  in  Fig.  137,  6,  was  employed  in  the  long  span  over  the 
River  Elbe  and  seven  insulators  per  string  were  used,  arranged 
with  the  strain  yoke  shown.  The  suspension  unit  here  is  only 
8.86  in.  in  diameter  with  6.69  in.  between  centers,  somewhat 


CROSS-ARMS,  HARDWARE,  AND  PINS          203 


FIG.  136. — Lauckhammer  insulator  unit. 


FIG.  137a.  FIG.  1376. 

Lauckhammer  strain  insulator  units. 


a  b  c 

FIG.  138. — Typical  European  suspension  insulator  units. 


204 


TRANSMISSION  LINE  CONSTRUCTION 


smaller  than  the  units  generally  adopted  in  this  country.  Fig. 
138,  a,  &,  c,  shows  other  typical  European  designs  which  it  will 
be  noted  are  one-piece,  though  somewhat  similar  in  design  to  the 
two-piece  units  manufactured  here. 

The  costs  of  suspension-type  insulators  is  greater  than  that  of 
the  pin  type  for  the  voltages  at  which  they  are  generally  listed, 
even  including  pins  in  the  case  of  that  type  and  suspension 
attachments  for  the  unit  type.  Costs  for  a  line  of  typical  in- 
sulators not,  however,  including  pins  or  fittings  in  this  case,  are 
shown  in  Fig.  139,  as  given  by  A.  O.  Austin  of  the  Ohio  Brass 
Company,  in  a  paper  read  before  the  Central  Electric  Railway 
Association.  As  a  comparison,  for  66,000-volt  service,  a  pin- 


04 

56 

.   48 

tn 
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• 

Curv 
Wlier 
AngU 
For! 
Nuin 

1                     | 
Weight  and  Cost  Curves 

8  based  on  Flash  over  Voltage  of  Insi 
Tested  under  Precipitation  of  0.2"pe 
of  46? 
ine  Voltage,  multiply  Wet  Flash-orei 
>er  corresponding  to  Factor  of  Safety 
of  Line  Connection, 
r  of  Safety            2345 

al  Grounded  1  °'87  °'58    °'43  °'3& 

XSStt***"  °-250-2,0 

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t. 

dators. 
Min.  at 

by 
and 

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$3.50 
$3.00 
$2.50 
$2.00  | 
$1.50 
$1.00 
$0.50 

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Facto 

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A  or 
Onefc 

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20        40        60        80       100       120       140      160       180      200      220 
Wet  Flash-over  in  K.V. 

FIG.  139. — Weight  and  cost  curves — pin  and  suspension  type  insulators. 

type  insulator  will  cost  from  $1.75  to  $2  and  a  suspension-type 
insulator  from  $2.50  to  $2.80,  for  insulators  alone  with  a  safety 
factor  of  about  2  at  wet  flash-over. 

For  shipment,  insulators  should  always  preferably  be  com- 
pletely assembled  and  cemented  at  the  factory,  including 
thimbles  for  pins,  where  the  separable  type  of  pin  is  used. 
For  convenience  and  safety  in  distribution,  large  pin-type  in- 
sulators are  shipped  three  in  a  crate;  in  this  regard,  it  may  be 
said  that  no  harm  will  be  done  by  incorporating  in  the  specifica- 
tions a  clause  covering  the  quality  of  the  material  and  work- 
manship employed  in  crating;  smaller  insulators  are  generally 
shipped  in  barrels. 


CROSS-ARMS,  HARDWARE,  AND  PINS          205 


In  the  unloading  of  a  car  of  insulators,  a  competent  man 
should  be  in  charge  to  inspect  and  check  over  the  shipment, 
not  only  for  the  purpose  of  establishing  claim  for  insulators 
broken  in  shipment,  but  to  keep  the  rejected  ones  separate 
from  the  good  ones  to  avoid  the  possibility  of  defective  insulators 
being  hauled  out  on  the  line  for  distribution.  Care  should  be 
taken  where  insulators  are  piled  in  the  open,  to  see  that  they  are 
arranged  so  that  no  part  of 


them  will  retain  water  which 
upon  freezing  may  burst 
them.  Insulators  not  under 
cover  are  subject  to  the  curi- 
osity of  the  local  inhabitants, 
who,  turning  a  crate  over  for 
inspection,  neglect  to  replace 
it,  so  that  it  is  well  to  keep  a 
close  watch  over  the  stock  in 
freezing  weather. 

The  distribution  of  insula- 
tors should  be  kept  apace 
with  the  work  and  only 
enough  laid  out  ahead  for 
each  day's  work;  a  team 
with  a  hay-rack  is  convenient 
for  handling  crated  or  bar- 
reled insulators,  and  one  man 
besides  the  teamster  can 
handle  the  work  nicely.  The 
cost  of  this  work  varies  of 
course  with  the  size  of  the 
insulators,  length  of  haul 
from  storage  yard,  and  length 
of  spans,  but  for  pressures  from  40,000  volts  to  60,000  volts, 
average  hauls  of  4  miles  through  Middle  West  farming 
country,  with  spans  about  125  ft.,  the  cost  will  be  from 
3  cents  to  5  cents  per  insulator,  man  and  team  figured  at  $4  a 
day  and  an  extra  man  at  $2;  where  long-span  tower  construction 
is  employed  the  cost  is  greater  and  through  rough  country  may 
be  double  the  figures  given. 

The  system  followed  in  the  erection  of  cross-arms  and  insula- 
tors varies;  in  steel  tower  work  the  cross-arms  are  of  course 


FIG.  140. — 110,000  volt  insulator  string. 


206          TRANSMISSION  LINE  CONSTRUCTION 


n    9  PnnnAr   \Vi  rf  CltranHorl  ,*2   Stf>f>l   f!'lhl 


J 

Connection 


FIG.   141. — Dead-end  insulator  arrangement. 


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6  a 

FIG.  142. — Strain  yokes. 


CROSS-ARMS,  HARDWARE,  AND  PINS          207 


integral  with  the  tower  structure,  in  steel  pole  work  this  is  also 
generally  the  case,  while  in  wooden  pole  work,  the  arms,  though 
usually  put  on  before  setting,  may  in  the  case  of  high  heavy 
poles,  be  left  off  and  installed  later. 

The  labor  cost  of  putting  on  high-tension  arms,  from  4  in.  X 
5  in.  to  5  in.  X7  in.  in  size  and  6  ft.  to  8  ft.  long,  averages  from 
8  cents  to  15  cents  when  done  on  the  ground  and  15  cents  to  25 
cents  when  done  in  the  air. 

Pin-type  insulators  are  as  a  rule  placed  on  towers  before  raising, 
but  seldom  on  poles  on  account  of  the  greater  liability  of  break- 


FIG.  143. — Arcing  rings. 

age  in  the  latter  case;  the  suspension  type  must  necessarily  be 
installed  after  the  structures  are  erected.  The  cost  of  in- 
stalling 66,000-volt  insulators  of  the  pin  type  ran  about  3  cents 
to  4  cents  each  for  tower  work  and  6  cents  to  8  cents  each  for 
wooden  pole  construction  where  they  were  put  on  after  setting, 
single-circuit  work  in  each  case.  Suspension-type  insulators  for 
the  voltages  to  which  they  are  generally  applied  can  be  installed, 
it  appears,  more  cheaply  than  the  pin  type  of  equal  voltage 
placed  after  setting.  It  is  interesting  to  note  that  in  the  110,000- 
volt  construction  of  the  Ontario  Hydro-Electric  Power  Commis- 


208 


TRANSMISSION  LINE  CONSTRUCTION 


sion,  a  foreman  with  three  men  installed  in  one  day  under 
favorable  circumstances,  as  high  as  120  insulators — forty  single- 
circuit  towers  spaced  about  500  ft.  apart.  These  insulators  are 

made  up  of  eight  10-in.  units 
with  an  overall  length  of  about 
5  ft.  and  weighing  about  100  Ib.  ; 
a  cut  of  this  insulator  is  shown 
in  Fig.  140.  Figuring  the  fore- 
man at  $4  and  the  three  men  at 
an  average  of  $2.50  a  day,  the 
total  labor  cost  for  erection  will 
be  $11.50  or  about  10  cents  per 
insulator. 

For  handling  dead-end  strains 
on  pin-type  insulators,  several 
of  them  are  usually  placed  in 
series  or  multiple-series;  Fig. 
141,  showing  a  typical  arrange- 
ment, with  the  tops  clamped  to 
a  longitudinal  equalizing-bar;  in 
suspension  insulator  work,  where 
the  strains  are  too  heavy  for  one 
insulator  a  yoke  arrangement 
for  two  or  three  sets  of  units,  as 
shown  in  Fig.  142,  a,  b}  is  used. 
In  the  case  of  lines  of  great 
capacity  where  the  dynamic  arc 
following  the  flash-over  of  an  in- 
sulator or  a  failure  is  of  enormous 


FIG.   144. — Arcing  rings. 


value,  it  is  necessary  to  protect  the  line  conductor  from  burning 
and  also  the  insulator  itself  from  being  destroyed  by  the  heat  of 
the  arc.  For  this  end,  arcing  rings  as  illustrated  in  Figs.  143  and 
144,  have  been  developed..  In  many  cases  also,  the  conductor  has 
been  protected  merely  with  a  serving  of  wire  or  with  a  sleeve  of 
sheet  metal,  or  a  protection  like  that  shown  on  the  clamp  of  the 
Ontario  Hydro-Electric  Power  Commission  in  Fig.  140,  has  been 
applied. 


CHAPTER  X 
GUYING 

The  character  of  the  guying  of  a  line  as  a  rule  reflects  the 
character  of  the  whole  construction;  if  it  be  poorly  and  cheaply 
done,  it  is  generally  the  case  that  there  is  neither  quality  nor 
finished  workmanship  in  the  remainder  of  the  construction,  and 
vice  versa. 

Guying  is  the  general  term  used  to  cover  that  phase  of  trans- 
mission line  work  that  has  to  do  with  the  external  reinforcement 
of  line  structures  to  help  resist  unusual  strains;  these  strains 
may  be  permanent,  due  to  angles  in  the  route  of  the  line,  or  as 
they  are  known  to  construction  men,  "  corners, "  to  "  dead-ends, " 
to  taps  for  branch  circuits,  etc.,  or  may  be  transient,  such  as 
would  be  set  up  by  extreme  weather  conditions,  broken  conduct- 
ors, etc.  To  resist  the  first  we  have  the  straight  "line  guying" 
as  it  is  known,  and  to  provide  against  the  second,  what  is  termed 
"storm  guying";  in  line  guying,  either  wire  guys  or  push 
braces  may  be  used,  in  storm  guying,  which  is  not  employed  in 
transmission  line  work  to  as  great  an  extent  as  it  is  in  telephone 
toll  line  work,  the  wire  guy  is  generally  employed. 

In  the  early  days  of  transmission  line  construction,  there  was 
more  or  less  prejudice  in  favor  of  push  braces  for  high-tension 
work  instead  of  wire  guys,  with  their  metallic  connection  to 
ground  carried  up  on  the  pole,  along  the  same  lines  as  where 
wooden  cross-arm  braces,  cross-arms  set  through  a  slot  in  the 
pole  and  keyed  with  wooden  pins,  etc.,  have  been  used,  and 
wire  guys  were  not  employed  very  freely.  With  better  know- 
ledge of  the  work,  and  more  especially  with  better  line  insulators, 
and  possibly  somewhat  on  account  of  the  cost  of  good  pole 
timber,  this  condition  has  been  reversed.  In  general,  it  may  be 
said  that  where  either  may  be  used,  about  the  only  advantages 
possessed  by  a  push  brace  are  that  it  cannot  be  so  easily  damaged 
maliciously,  can  be  arranged  to  take  both  tension  and  com- 
pression, and  adds  somewhat  to  the  strength  of  the  line  in  a 
longitudinal  direction;  on  the  other  hand,  brace  poles  cannot  be 
14  209 


210 


TRANSMISSION  LINE  CONSTRUCTION 


adapted  to  varying  conditions,  are  expensive  in  the  larger  sizes, 
and  are  liable  to  destruction  from  grass  fires  and  lightning. 
Wire  guys,  on  account  of  their  greater  flexibility,  cheapness 
under  general  conditions,  and  ease  of  installation,  are  now  used 
practically  altogether  for  the  external  reinforcement  of  line 
supports. 

Typical   methods   of  setting  single  and   double  push  braces, 
used  in  general  pole  line  work,  are  shown  in  Figs.  145  and  146; 


t 


Contact  Surfaces  to  both 
have  a  heavy  coat  of 
Standard  Paint.        / 


Two  2  x  12  Boards  3  fi 
Long  Crossed  as  shown" 


FIG.  145.— Push  brace. 

to  increase  the  bearing  area  of  the  brace  where  the  ground  end 
is  of  smaller  diameter  than  is  safe  under  the  soil  conditions,  it 
will  be  noted  that  two  pieces  of  plank  are  placed  under  the  butt; 
a  large  flat  stone,  say  18  in.  to  24  in.  on  a  side,  may  be  used 
very  well  in  place  of  the  plank,  and  where  the  brace  thrusts  into 
hard  ground  or  a  rock  ledge,  of  course  nothing  will  be  required. 
Where  a  combination  push  and  pull  brace  is  desired,  the  brace 
pole  should  be  set  deeper,  as  shown  in  Fig.  147,  and  have  a  slug 
or  deadman,  apiece  of  sound  pole  5  ft.  to  6  ft.  long  and  10  in.  to 
12  in.  in  diameter,  bolted  to  its  butt  as  shown. 


GUYING 


211 


Standard  methods  of  wire  guying  are  shown  in  Figs.  148  and 
149;  these  are  the  arrangements  ordinarily  followed  in  transmis- 
sion line  work  for  light  and  heavy  angles  respectively;  a  push 
brace  should  preferably  be  used  where  the  line  is  built  on  or 
closely  adjacent  to  a  highway,  etc.,  where  the  " corner"  is  such 
that  a  wire  guy  would  strike  in  the  road  and  it  would  be  neces- 
sary to  carry  the  guy  across  the  road  to  a  guy  stub.  Where  a 
corner  is  heavy  enough  to  require  the  guying  shown  in  Fig.  149, 


i 


Contact  Faces  to  both 
have  a  heavy  coat  of 
Standard  Paint. 


FIG.  146. — Double  push  brace. 

the  poles  on  either  side  of  the  corner  should  be  double-armed  and 
head  guyed  as  shown.  Special  head  guying  will  also  be  required 
where  severe  vertical  angles  are  encountered,  such  as  will  be  met 
with  in  hilly  country,  and  also  where,  on  account  of  the  contour 
of  the  country,  the  crossing  of  rivers  or  swamps,  etc.,  unbalanced 
spans  may  be  called  for,  necessitating  side  guying  also  if  the  spans 
be  long.  At  railroad  crossings  the  two  poles  on  each  side  of  the 
crossing  span  are  usually  required  to  be  strongly  guyed. 
Where  conditions  are  such  that  it  is  impossible  to  secure  right- 


212 


TRANSMISSION  LINE  CONSTRUCTION 


of -way  for  a  guy,  such  as  may  occur  where  a  high-tension  line  is 
built  along  a  public  highway  or  in  cases  where  easement  for  the 
erection  of  a  line  is  secured  only  on  one  side  of  a  line  fence  and  it 
is  impossible  to  arrange  for  guying  privileges  on  the  other  side, 
a  truss  arrangement  as  shown  in  Fig.  150,  known  as  a  "buck- 
stayed"  or  self-supporting  pole  must  sometimes  be  used.  The 
employment  of  this  means  of  avoiding  the  placing  of  the  regular 
guys  is  expensive  and  less  satisfactory  than  a  straight  guy,  and 
should  not  be  used  where  any  other  solutions  of  the  problem  are 
possible. 


Contact  Faces  to  both 
have  a  heavy  coat  of 
Standard-Paint. 


FIG.   147. — Push  and  pull  brace. 

Storm  guying  consists  in  reinforcing  poles  at  certain  intervals 
along  the  straight  stretches  of  the  line,  to  resist  strains  in  all 
four  directions  so  as  to  localize  structural  line  failures  and  pre- 
vent-them  from  becoming  cumulative  on  long  tangents.  Fig. 
151  shows  the  customary  installation  of  storm  guys,  which, 
however,  have  not  been  much  used  in  transmission  line  work, 
though  there  are  many  cases  where  they  should  really  be 
employed. 


GUYING 


213 


For  push  braces,  the  size  pole  required  depends  upon^the 
length  of  the  line  pole  and  the  load  it  carries,  but  in  no  case 
should  a  brace  be  used  having  a  top  diameter  of  less  than  6  in. ; 
the  brace  should,  under  ordinary  circumstances,  be  set  with  its 
butt  about  3  ft.  in  the  ground  and  at  a  distance  away  from  the 
line  of  about  one-third  the  height  of  the  pole,  measured  along 
the  surface  of  the  ground;  braces  should  be  similar  to  the  line 
pole  and  if  preservative  treatment  be  given  the  line  poles, 


FIG.  148. — Standard  wire  guy. 

the  brace  pole  should  also  be  treated.  At  the  point  of  contact 
of  the  brace  with  the  pole,  the  end  of  the  brace  should  be  scarfed 
to  fit  but  the  pole  itself  should  not  be  gained  in  any  way. 

A  good,  even  bearing  of  the  brace  upon  the  pole  should  be 
secured,  the  ordinary  method  of  laying  out  a  brace  and  of 
determining  the  correct  bevel  of  the  brace  top  being  to  measure 
the  distance  from  the  brace  through  bolt  to  the  ground  and  at 
right  angles  thereto,  the  distance  from  the  pole  to  the  brace  hole, 
then  starting  from  the  ground  line  of  the  brace  pole  as  it  lies 


214          TRANSMISSION  LINE  CONSTRUCTION 


For  Angles  over  30   Double-arm  and  Head 
Guy  Poles  "A"  and'!B"as  shown. 


FIG.   149. — Heavy  comb  guying. 


"'V, 


FIG.  150. — "  Buck-stayed"  or  self-supporting  pole. 


GUYING  215 

on  the  ground,  measure  out  these  distances  with  a  right  angle 
between  them  and  the  bevel  of  the  brace  end  will  be  indicated  by 
the  line  of  the  tape  and  this  will  be  naturally  the  point  at  which 
the  pole  is  to  be  sawed  off,  the  taper  of  the  line  pole  being  allowed 
for.  While  this  is  the  method  of  laying  out  used  by  old-time 
line  foremen  generally,  a  far  simpler  method  is  to  measure  directly 
from  the  point  on  the  pole  where  the  center  of  the  brace  will 
strike,  to  the  center  of  the  brace  hole  and  take  the'  bevel  with  a 
bevel-square,  from  the  line  of  the  tape. 


•  s~s 

FIG.   151. — Storm  guying. 

The  top  of  the  brace  pole  should  be  carried  up  as  far  on  the  pole 
as  clearances  to  the  conductors  will  allow,  with  due  consideration 
of  the  strain  and  the  cost  of  brace-pole  timber  of  the  various 
lengths. 

The  erection  of  brace  poles  in  the  lighter  sizes  may  be  ac- 
complished by  piking,  but  as  the  guying  crews  should  preferably 
be  made  up  of  as  few  men  as  possible,  they  are  in  most  cases 
pulled  up  with  a  pair  of  blocks.  If  the  timber  be  untreated,  a 
liberal  coat  of  tar,  paint,  or  some  good  preservative,  should  be 
applied  to  both  surfaces  at  the  point  of  contact;  the  through 


216 


TRANSMISSION  LINE  CONSTRUCTION 


bolt  should  be  galvanized,  be  not  less  than  3/4  in.  in  diameter, 
and  should  be  provided  with  heavy  washers  on  each  side. 

In  the  installation  of  wire  guys  the  location  of  the  point  of 
attachment  of  the  guy  to  the  pole  in  high-tension  work  is  deter- 
mined by  the  electrical  clearance  required,  though  for  pin-type 
insulators,  as  a  rule,  the  guy  can  be  brought  up  immediately 


FIG.  152. 

under  the  bottom  cross-arm;  where  suspension  insulators  are 
employed,  the  guy  under  ordinary  arrangements,  will  have  to 
be  placed  lower  down  and  greater  clearances  allowed.  Clever 
angle  construction  where  long-span  (300  ft.)  wooden  pole  work 
with  suspension  insulators  is  employed,  is  shown  in  Fig.  152; 
this  type  of  corner  construction  has  been  used  by  the  Madison 


GUYING  217 

River  Power  Company  and  works  out  very  satisfactorily.  The 
condition  to  be  sought  for  in  any  of  this  work  is  to  bring  the 
guy  or  brace  as  near  as  possible  to  the  point  of  the  resultant  of 
the  strains  set  up  by  the  deflection  of  the  wires. 

The  guy  is  attached  to  the  pole  by  taking  two  complete  turns 
around  it  and  fastening  with  one  three-bolt  clamp  for  general 
conditions  and  two  where  unusually  heavy  strains  are  encoun- 
tered; the  ends  of  the  guys  should  extend  8  in.  or  10  in.  beyond 
the  end  of  the  clamp  and  should  be  lightly  made  up  to  the  guy 
proper  by  serving  with  a  few  turns  of  one  of  the  strands  of  the 
cable.  A  strain  insulator  should  be  made  up  into  the  guy, 
about  6  ft.  or  8  ft.  out  from  the  pole;  here,  instead  of  using 
clamps,  many  companies  make  up  the  cable  on  either  side,  the 
work  being  done  as  much  as  possible  by  the  men  when  weather 
conditions  prevent  work  outside;  where  the  connections  are 
made  up  two  or  three  turns  should  be  made  with  the  full  cable  be- 
fore unstranding  and  serving;  galvanized  guy  thimbles  should 
be  used  at  all  points  where  a  metal  to  metal  turn  through  eyes, 
etc.,  is  made  with  the  guy  strand. 

With  the  guy  made  up  on  the  pole,  the  other  end  of  it  is 
passed  through  the  eye  of  the  anchor  rod,  the  slack  pulled  out, 
and  a  pair  of  4-in.  or  6-in.  double  blocks  with  a  come-a-long,  pref- 
erably of  the  eccentric  type,  at  each  end,  is  hooked  on  to  the 
guy  proper  and  to  the  end;  the  guy  is  then  pulled  up  to  the 
required  tautness,  usually  enough  to  rake  the  pole  back  a  little 
so  that  it  will  be  nearly  straight  when  the  strain  is  placed  upon 
it,  and  is  fastened  with  a  three-bolt  clamp  in  a  manner  similar 
to  that  of  the  other  end. 

For  wire  guys,  only  stranded  cable,  preferably  seven-strand, 
should  be  used,  and  it  should  be  of  first-class  material  and 
galvanized.  For  transmission  line  work  of  any  importance 
whatever,  3/8-in.  strand  should  be  the  smallest  size  allowed 
on  the  job  regardless  of  the  strain;  a  schedule  should  be  worked 
out  for  the  direction  of  the  foreman  which  will  give  in  tabular 
form  the  size  and  grade  of  strand  to  be  used  for  various  ranges 
of  line  angles  and  distances  of  anchor  from  butt  of  pole,  thus 
standardizing  the  construction  and  ensuring  uniformity  in  the 
work;  two  or  three  different  strands  will  cover  all  ordinary 
conditions.  In  the  case  of  a  line  that  has  been  staked  out  with 
an  instrument,  the  guy  anchor  locations  may  also  have  been 
made  and,  from  the  data  as  to  the  horizontal  deflections  in 


218 


TRANSMISSION  LINE  CONSTRUCTION 


the  line  and  the  vertical  angles  of  the  guys,  the  strain  and  the 
size  of  strand  required  can  be  determined  in  the  office  for  each 
and  every  case  and  an  exact  definite  schedule  given  to  the 
foreman. 

There  are  four  regular  grades  of  stranded  guy  or  messenger 
cable,  the  standard,  the  Siemens-Martin,  the  high  strength 
and  the  extra  high  strength;  the  first  two  are  the  grades  used 
for  general  guying  purposes,  the  latter  two  being  employed 
very  little  in  transmission  work  except  as  ground  wire  or  as 
conductors  for  long-span  river  crossings,  etc.,  where  their  great 
tensile  strength  makes  them  valuable;  the  standard  is  the 
cheapest  and  the  most  easily  handled,  and  is  less  susceptible 
to  injury  from  kinking  or  nicking,  etc.,  than  the  Siemens-Martin 
or  the  other  higher-strength  strands  and  is,  therefore,  the  most 
used  for  guy  work.  Where  heavy  strains  are  encountered  and 
where  first-class  construction  all  the  way  through  is  demanded, 
Siemens-Martin  may  be  used;  this  grade  shows  a  greater 
uniformity  in  strength  and  toughness  than  the  standard  and 
is,  therefore,  often  specified  where  the  strains  could  be  as  well 
handled  with  the  standard.  On  the  other  hand,  it  appears 
that  the  galvanizing  on  the  steel  higher-strength  strand  does 
not  afford  the  effective  life  that  it  does  on  standard. 

In  Table  IX  is  given  data  on  the  Siemens-Martin  grades  of 
strand,  with  approximate  prices  prevailing  in  1911  for  purchases 
in  mile  quantities. 

TABLE  IX 


Standard  strand,        !  Siemens-Martin  strand, 

galvanized 

extra  galvanized 

Diam., 

Approx.  wt.  in 

Approx. 

Price  per 

Approx. 

Price  per 

in. 

|  Ib.  per  1000  ft.     strength,  Ib. 

1000  ft.     strength,  Ib. 

1000  ft. 

1    . 

1/4 

I 
125 

2,300 

$6.20 

3,060 

$8.00 

5/16 

210 

3,800 

7.90 

4,860 

10.80 

3/8 

295 

5,000 

9.70 

6,800 

14.40 

7/16 

415 

6,500 

13.20 

9,000 

18.40 

1/2 

510 

8,500 

15.75           11,000 

22  .  40 

5/8 

19  000 

34  80 

, 

GUYING 


219 


The  figures  on  prices  will  give  a  comparison  of  the  relative 
costs  of  the  two  grades;  it  will  be  noted  that  the  standard,  as 
given,  is  with  single  galvanizing  and  the  Siemens-Martin  with 
double  dip.  The  cost  of  the  standard  for  extra  galvanizing  is 
about  10  per  cent,  more  than  the  tabulated  figures. 

The  galvanizing  of  guy  strand  in  particular  of  all  line  material, 
should  be  first  class  and  should  be  in  accordance  with  the  recog- 
nized standards  for  that  work,  and  should,  preferably,  be  double 
dip.  A  set  of  general  specifications  for  galvanizing  giving 
methods  for  the  conduct  of  tests,  is  given  in  the  Appendix. 

For  the  fastening  of  guy  strand,  three-bolt  galvanized  clamps 
should  always  be  used,  rather  than  two-bolt;  clamps  of  the 
Crosby  type  are  not  suitable  for  permanent  installation;  for 
ordinary  work,  the  standard  rolled  steel  or  malleable-iron 
clamps  are  satisfactory,  but  where,  for  special  work,  the  high- 
strength  strands  may  be  required,  clamps  with  curving  grooves 


FIG.  153. — Guy  clamp. 

such  as  that  illustrated  in  Fig.  153  are  preferable;  all  clamps 
should  be  galvanized  to  correspond  with  that  of  the  strand 
used  and  should  have  grooves  rounded  off  a  little  at  the  ends 
to  prevent  any  possibility  of  cutting.  In  addition  to  the  regular 
flat  typ'e  of  clamp,  there  are  several  patented  types  that  are 
very  good. 

Anchors  for  guys  are  numerous;  everyone  with  a  genius  for 
mechanical  contrivances  appears  to  have  brought  out  a  patent 
anchor.  Among  them  are  the  screw  type,  the  scoop  or  flat 
expanding  plate  designs  that  are  buried  with  the  use  of  an  earth 


220 


TRANSMISSION  LINE  CONSTRUCTION 


auger,  the  straight  malleable-iron  plate  deadman,  and  various 

kinds  of  harpoon-like  designs. 

The  first  of  these  is  nothing  more  than  an  earth  screw,  see 
Fig.  154,  which  in  the  smaller  sizes  is  set  in 
the  ground  by  means  of  a  special  wrench, 
which  is  really  a  long-shank  socket  wrench 
with  adjustable  handles,  that  upon  the  un- 
screwing of  the  threaded  eye  at  the  end  of 
the  anchor  rod,  is  slipped  over  the  rod  and 
down  to  engage  a  square  shoulder  on  the 
anchor  proper;  in  the  larger  sizes,  such  as 
shown  in  cut,  the  rod  is  made  heavy  enough 
so  that  the  anchor  can  be  installed  by  insert- 
ing a  digging  bar  through  the  eye  and  using  it 
as  a  lever  in  turning  the  anchor  into  place. 
The  advantage  of  the  screw  type  of  anchor, 
of  course,  is  the  fact  that  it  does  away  with 
digging,  and  the  installation  cost  is  conse- 
quently low.  For  light  strains  in  average 
soil,  it  works  out  quite  well,  though  it  is 
liable  to  creep  under  a  good  steady  strain  and 
is  difficult  to  set  in  stony  or  coarse  gravelly  soil. 
The  scoop  and  the  expanding  types  of 

anchors  require  the  digging  of  holes  of  small  diameter  with  an 


FIG.  154.— 8-in. 
anchor. 


FIG.  155. 


FIG.  156. 


earth  auger,  and  then  for   a   certain   type   the  enlargement  of 
the  bottom   of  the  hole  by  means  of  a  special  tool,  as  shown 


GUYING  221 

in  Fig.  155;  the  blade  of  this  latter  type  of  anchor,  shown  in 
Fig.  156,  is  about  twice  as  long  as  it  is  wide  and  is  suspended 
from  the  rod  so  that  it  can  be  swung  on  its  short  axis  to  allow 
its  introduction  in  the  hole,  which  is  bored  slightly  larger  in 
diameter  than  the  width  of  the  blade;  upon  reaching  the  en- 
larged bottom  of  the  hole  it  is  pushed  into  its  natural  position  at 
right  angles  to  the  axis  of  the  rod,  by  means  of  a  digging  or  a 
tamping  bar. 

The  expanding  types  are  placed  in  straight  auger  holes  in  the 
same  manner  as  the  foregoing  and  then  by  hammering  a  shoulder 
or  lug  with  a  tamping  bar,  multiple  disks  or  arms  are  projected 
into  the  walls  of  the  holes,  the  special  claims  of  the  manufacturers 
of  this  type  of  anchor  being  that  the  bearing  is  on  undisturbed 
earth. 

For  light  lines  and  for  telephone  work,  several  different  types 
of  anchors  have  been  developed  which  present  only  a  nominal 
resistance  to  being  driven  into  the  ground  with  a  maul  and 
which,  upon  a  reversal  of  strain  or  upon  giving  the  rod  a 
turn,  project  blades  or  wings  into  the  earth,  acting  like  a  barbed 
arrow. 

While  any  of  the  patent  anchors,  such  as  described  above  and 
others,  have  their  own  sphere  of  usefulness,  the  criterion  of  their 
value  in  any  particular  soil,  is  the  effective  bearing  area  that  they 
possess.  Consequently  they  have  not  been  given  much  serious 
consideration  in  heavy  transmission  work,  though  it  may  be  truly 
said  that  very  little  intelligent  effort  is  usually  made  to  seek  the 
most  economical  and  satisfactory  appliances  in  the  guying  of 
most  high-tension  lines.  Therefore,  the  "safe  and  sane"  theory 
has  been  applied  to  anchorages  for  guys,  and  the  deadman  type 
is  often  used  throughout,  where  at  points  of  lighter  strain,  the 
use  of  some  other  type  would  be  as  satisfactory  and  of  lower  cost. 

The  deadman,  slug,  or  sleeper  anchor  consists  usually  of  a 
piece  of  sound  pole,  10  in.  to  16  in.  in  diameter  and  from  5  ft.  to 
8  ft.  long,  buried  6  ft.  or  7  ft.  in  the  ground;  where  it  is  impossible 
to  go  as  deep  as  this  economically,  the  length  and  diameter 
of  the  deadman  is  increased  or  the  bearing  area  extended  by 
placing  timbers  over  the  log  at  right  angles  to  it.  To  the  dead- 
man is  attached  a  galvanized  anchor  rod,  usually  3/4  in.  or  1  in. 
in  diameter  and  7  ft.  to  8  ft.  long,  provided  with  a  4-in.  X4-in.  X 
1/4-in.  galvanized  washer;  Fig.  157  shows  a  typical  deadman 
anchor.  Wherever  the  soil  will  stand  it,  the  hole  for  the  deadman 


222 


TRANSMISSION  LINE  CONSTRUCTION 


should  be  dug  along  the  lines  shown  dotted  in  Fig.  157,  the 
object  being  to  disturb  the  earth  in  direct  bearing  as  little  as 
possible  so  that  there  will  be  no  possibility  of  anchor  creepage. 
Where  treated  poles  are  used,  the  deadman  should,  of  course,  be 
subjected  to  the  same  process.  In  place  of  wooden  deadmen, 


Dig  Channel  for  Anchor 
,od  after  hole  is  complete 


Size  of  Dead-man  as  per 
Specifications-LD-18 


Galv.  Washer 

FIG.   157. — Dead-man  or  long  anchor. 

stones  and  malleable  or  cast-iron  plates  are  used  somewhat  where 
their  area  is  sufficient  to  handle  the  strain,  and  experiments  have 
been  made  with  concrete,  tamped  into  the  hole  after  the  insertion 
of  rod  and  reinforcing  steel. 


Grout  in  with  neat 
Portland  Cement. 


FIG.   158. — Rock  anchor. 

It  often  happens  that  anchors  must  be  set  in  rock,  and  Figs. 
158  and  159  show  methods  of  doing  this.  The  setting  shown  in 
Fig.  158  is  for  places  where  hard  homogeneous  ledge  rock  is 
encountered,  and  eye-bolts  1  in.  or  so  in  diameter  and  12  in.  to 
16  in.  long  should  be  used;  the  eye-bolt  should  be  nicked  or 


GUYING  223 

scarred  along  its  shank  or  upset  slightly  at  its  lower  end  and 
should  be  grouted  in  with  neat  portland  cement,  care  being  exer- 
cised to  see  that  the  hole  is  drilled  only  a  little  larger  than  the 
bolt.  Where  the  rock  is  softer  or  stratified,  an  ordinary  guy  rod, 
split  and  fox-wedged  into  a  hole  2  ft.  or  3  ft.  deep  and  set  in  neat 
portland  cement  as  shown  in  Fig.  159,  is  very  satisfactory. 

The  cost  of  the  different  patent  anchors  varies  with  the  locality 
and  the  quantities  purchased,  but  in  amounts  of  fifty  or  so,  the 
plain  screw-type  will  cost  in  the  8-in.  size  about  $4.50  each,  the 
10-in.,  $6.50  and  the  12-in.,  about  $9.10  each,  laid  down  through- 
out the  Middle  West;  the  scoop  type,  such  as  the  Miller,  with  an 
8-in.  X20-in.  plate  and  3/4-in.  x8-ft.  galvanized  rod  will  cost 
laid  down  in  the  Middle  West  about  $2.50  each  and  with  a  9-in.  X 


FIG.  159. — Rock  anchor. 

25-in.  plate  and  a  1-in. X9-ft.  galvanized  rod  about  $4  each; 
the  plain  malleable-iron  plate  type  of  anchor  will  cost  about 
$1.60  each  for  average  strains  encountered  with  30-ft.  to  40-ft. 
poles,  and  $2.75  each  for  45-ft.  to  60-ft.  poles. 

The  old  reliable,  the  deadman  or  log  anchor,  is  the  cheapest 
of  all  as  far  as  cost  of  material  is  concerned,  a  6-ft.  slug  costing 
not  more  than  40  cents  or  50  cents,  with  a  3/4-in.  X8-ft.  .galva- 
nized rod  at  about  60  cents  and  about  5  cents  for  fitting,  giving 
a  total  cost  of  the  anchor  ready  to  distribute  at  $1.05  to  $1.15 
each. 

The  strain  that  the  different  types  of  anchors  will  hold  in 
various  kinds  of  soil  is  largely  a  matter  of  conjecture,  as  no  series 
of  comparative  tests  have  ever  been  made  to  the  knowledge  of  the 


224 


TRANSMISSION  LINE  CONSTRUCTION 


writer.  The  usual  assumption  made  in  the  calculation  of  the 
strains  that  an  anchor  will  stand,  is  that  the  ultimate  load  is  the 
weight  of  the  volume  of  earth  included  by  lines  drawn  from  the 
edge  of  the  exposed  surface  of  the  earth  at  an  angle  of  about 
30  degrees  from  the  vertical,  plus  the  weight  of  the  anchor. 
This  assumption  holds  fairly  well  with  tests  made  by  D.  R. 
Scholes  of  the  Aermotor  Company,  noted  by  him  in  the  1907 
Transactions  of  the  American  Institute  of  Electrical  Engineers 
and  with  experiments  carried  out  by  Mr.  Fraser  of  the  Southern 


FIG.  160. — Guy  insulator. 

Power  Company  also  reported  in  the  1907  Transactions,  but  it  is 
questionable  how  it  applies  to  strains  at  varying  angles  from 
the  vertical  and  for  surfaces  other  than  flat,  such  as  that  pre- 
sented by  a  log;  and  it  is  natural  that  the  general  assumption 
will  not  hold  for  wet  soils. 

In  the  wire  guying  of  wooden  poles,  it  is  now  the  general  practice 
to  insert  some  kind  of  a  strain  insulator  in  the  guys  about  6  ft. 
or  8  ft.  out  from  the  pole,  the  insulator  being  of  wood,  porcelain 
or  composition;  the  function  of  this  insulator  is  to  prevent 


FIG.   161. — Wood  guy  insulator. 

injury  or  damage  resulting  from  contact  of  persons  or  animals 
with  a  guy  which  may  be  charged  from  leaky  insulations,  etc., 
and  also  to  prevent  burning  of  the  pole  at  the  point  of  attachment 
of  a  guy  due  to  similar  conditions. 

Wooden  insulators,  either  the  type  shown  in  Fig.  160  or  a 
design  like  Fig.  161,  the  latter  usually  "home-made/'  have  been 
used  to  a  great  extent  in  transmission  line  work,  the  former  as 
a  rule  in  lighter  and  lower-voltage  work  and  the  latter  in  lengths 
as  great  as  6  ft.  or  8  ft.  in  the  heavier  construction  and  higher 


GUYING 


225 


voltages.  The  wood  strains  shown  in  Fig.  160  are  made  in  sizes 
from  6  in.  to  48  in.  and  longer,  for  ultimate  breaking  strains  up 
to  20,000  Ib.  or  more;  the  wood  generally  used  is  hickory  and  is 
given  a  preservative  and  insulating  treatment.  On  a  typical 
high-tension  line  in  the  Middle  West  the  guy  strain  insulators 
were  of  2  1/2-in.  X2  1/2-in.  X30-in.  oak,  boiled  in  linseed  oil, 
the  design  being  similar  to  that  shown  in  Fig.  161;  where  larger 
strain  insulators  have  been  employed,  such  as  4-in.  X4-in.  X6-ft. 
oak  used  in  some  Western  lines,  they  have  often  been  used  un- 
treated. Where  wooden  insulators  are  used,  however,  they  should 
always  be  given  some  treatment  and  as  a  general  thing  hard 
maple,  oak  or  hickory  should  be  used. 

The  objection  to  the  use  of  wood  is  that  it  is  susceptible  to 
destruction  by  burning  in  case  of  heavy  leakage;  for  this  reason 
insulators  of  porcelain,  interlinked  or  cemented,  or  some  of  the 
compositions,  have  been  installed  in  the  latter  lines  to  a  great 
extent. 


FIG.  162. — Porcelain  circuit  breaks. 

Porcelain  is  the  most  favored  for  high-class  line  construction, 
though  its  cost  is  appreciably  higher  than  that  of  wooden  insula- 
tors for  the  average  sizes  that  have  been  used  in  transmission 
work.  There  are  two  general  types  of  porcelain  circuit  breakers 
that  have  been  used  for  guy  work,  the  first,  a  straight  ball  or 
"goose  egg"  as  shown  in  Fig.  162,  and  the  other,  designs  of  the 
same  type  used  for  suspension  insulator  work,  such  as  are 
illustrated  in  Figs.  163  and  164. 

The  first-mentioned,  the  ball  type,  is  used  mostly  on  lower- 
voltage  lines,  while  the  latter  kinds  are  beginning  to  be  used 
where  heavy  wood  strains  have  been  used  heretofore. 

The  use  of  composition  strain  insulators  is  confined  mostly  to 
distribution  and  street  railway  work,  though  at  times  employed 
on  lines  which  carry  the  lower  voltages. 


226  TRANSMISSION  LINE  CONSTRUCTION 

In  cost  the  wood  strains  for  the  average  of  sizes  will  run  about 
the  cheapest,  though  some  of  the  porcelain  designs  will  com- 
pete very  closely  for  certain  conditions;  a  14-in.  design  will 
cost  about  28  cents  each  laid  down  in  quantities  of  100  in  the 
Middle  West,  and  the  48-in.  about  75  cents. ;  these  figures  are  for 
manufactured  insulators  and  those  of  the  design  shown  in  Fig. 
161,  made  up  locally  will  cost,  for  a  2  1/2-in.  X2  1/2-in.  X 48-in. 
oak  insulator  boiled  in  linseed  oil  or  paraffine,  from  50  cents  to 
60  cents  each  in  like  quantities. 


FIG.  163. 

The  ball  type  of  porcelain  strain  insulators  in  the  sizes  used  in 
the  lighter  construction  will  cost  from  20  cents  to  30  cents  laid 
down  almost  anywhere  in  the  East  or  Middle  West;  the  cemented 
type  of  strain  insulator,  similar  to  the  kind  shown  in  Fig.  163,  will 
cost  for  the  10-in.  size,  about  90  cents  to  $1  f.o.b.  factory  with 
the  required  fittings,  and  various  manufacturers  list  their  in- 
sulators of  this  diameter  and  general  design  to  stand  from  9000 
Ib.  to  18,000  Ib.  Smaller  sizes  of  'this  design  of  insulator  are 
being  brought  out  especially  for  guying  work. 

The  interlinking  types,  such  as  illustrated  in  Fig.  164,  have  an 
advantage  over  the  design  just  discussed,  in  that  they  provide  a 
mechanical  connection  between  the  two  parts  of  the  guy  in  the 


GUYING 


227 


event  of  the  failure  of  the  insulator.  This  type  in  the  6  1/2-in. 
size  will  cost  about  75  cents  each  at  the  factory  and  will  stand  an 
ultimate  load  of  about  7500  lb.,  while  the  10-in.  size  will  cost  about 
twice  as  much.  This  type  of  insulator  is,  in  fact,  practically  a 
ball  type  of  insulator  with  the  grooves  enclosed  and  a  flange 
added  to  increase  the  leakage  surface. 

The  composition  insulator  is  so  rarely  used  in  transmission 
line  work  that  data  on  the  various  sizes  are  unnecessary;  as  a 
rule,  the  costs  are  above  those  of  any  of  the  others. 


FIG.  164. 


Cost  data  on  the  guying  of  transmission  lines  are  difficult  to 
secure  and  the  unit  figures  obtained  are  extremely  variable, 
owing  to  the  great  differences  in  conditions;  one  line  may  require 
guys  at  average  distances  apart  of  a  quarter  of  a  mile  and 
another  at  intervals  of  a  mile;  in  one  case  the  soil  may  be  a 
sandy  loam  and  in  another  it  may  be  tough  hard  clay;  the  work 
may  be  carried  on  in  the  summer  time  here  and  in  the  midst  of 
winter  there.  All  of  these  factors  must  be  taken  into  considera- 


228  TRANSMISSION  LINE  CONSTRUCTION 

tion  in  making  comparisons  of  costs;  furthermore,  even  under 
practically  similar  conditions  as  to  type  of  construction,  soil, 
climate,  weather,  etc.,  the  engineer  for  one  line  may  have  different 
ideas  as  to  what  depth  of  set  and  size  of  anchors  will  be  required 
for  a  certain  strain  and  this  again  makes  for  variations  in  costs. 

For  transmission  line  work  a  crew  of  four  men 'and  a  team, 
made  up  of  a  lineman  sub-foreman,  one  lineman,  a  groundman, 
and  a  team  and  teamster,  make  a  good  size  gang  for  average 
work;  the  crew  should,  under  general  conditions,  be  kept  as  small 
as  possible  as  in  transmission  work  the  guys  are  usually  not  at 
very  close  intervals  and  if  a  large  gang  is  used  the  percentage  of 
dead  time,  that  is,  time  required  in  moving  from  one  job  to 
another,  wTill  be  excessive. 

The  cost  of  setting  push  braces  for  a  line  of  9-in.  top,  40-ft. 
poles  with  a  crew  of  the  foregoing  size,  with  the  foreman  at 
$3,  lineman  at  $2.75,  groundman  at  $2  and  team  and  man  at 
$4  a  day  was  about  $2.65  each,  not  including  general  supervision 
or  the  hauling  of  the  pole,  the  latter  averaging  about  45  cents. 
These  poles  were  culls  from  the  line  poles  and  were  very  heavy; 
they  were  set  3  1/2  ft.  in  the  ground  and  were  about  32  ft.  long; 
the  soil  was  a  sandy  loam,  the  work  was  done  in  the  late  fall 
and  winter  and  the  braces  averaged  about  11/2  miles  apart,  guys 
being  generally  used.  Push  braces  for  a  line  of  7-in.  top,  35-ft. 
northern  cedars,  using  brace  poles,  28  ft.  to  29  ft.  long  with  6-in. 
tops,  cost  for  erection  labor,  exclusive  of  hauling  and  general 
supervision,  about  $1.60  each  with  a  wage  scale  about  the  same 
as  for  the  preceding  case;  the  soil  was  a  medium  clay  and  the 
braces  were  about  1  mile  apart. 

The  cost  of  placing  guys  complete  for  a  line  of  40-ft.  poles, 
using  deadmen  6  ft.  long  and  from  12  in.  to  16  in.  in  diameter 
buried  6  ft.  deep  in  sandy  loam,  including  the  placing  of  the  guy, 
with  a  wood  strain  cut  in,  and  the  hauling,  but  not  including 
general  supervision,  was  about  $2.75  each;  3/8-in.  standard  and 
Siemens-Martin  strand  were  used.  The  crew  consisted  of  a 
foreman  at  $3,  one  lineman  at  $2.75,  two  groundmen  at  $2,  and 
a  team  and  man  at  $4  a  day;  the  work  was  carried  on  in  the  late 
fall. 

For  a  line  of  7-in.  top,  35-ft.  cedars,  log  anchors  5  ft.  to  6  ft. 
long  and  about  12  in.  in  diameter,  buried  about  6  ft.  in  medium 
clay  soil,  with  a  3/8-in.  standard  strand  guy  placed,  including  a 
porcelain  strain  insulator  in  same,  cost  about  $3.90  each,  not 


GUYING  229 

including  general  superintendence;  the  wage  scale  was  about  the 
same  as  for  the  previous  case. 

In  Engineering-Contracting  for  May  27,  1908,  the  labor  cost  of 
installing  deadmen  anchors  with  guys  complete,  is  given  as  $2.03; 
this  was  for  a  telephone  job  in  a  small  town  and  the  standard 
pole  height  was  30  ft.;  no  data  is  given  as  to  wage  scale,  size  of 
anchor,  kind  of  soil,  etc. 

In  the  same  journal  for  Feb.  5,  1908,  the  total  labor  cost  for 
installing  guys  with  ground  stubs  is  given  as  $3.25  each;  the  line 
poles  here  were  30  ft.  to  33  ft.  chestnut,  the  soil  was  a  red  sandy 
clay  and  the  wage  scale  for  a  ten-hour  day  was,  foreman  $3, 
lineman  $2.50, -groundman  $1.50,  and  team  and  man  $4.50. 


CHAPTER  XI 

STRINGING  WIRE 

For  the  commercial  transmission  of  electrical  energy,  we 
have  available  copper,  aluminum,  bi-metallic,  and  iron  or 
steel  wire. 

Copper  has  been  the  most  used  in  all  kinds  of  construction, 
possessing  as  it  does  the  highest  conductivity,  a  strength  and 
hardness  greater  than  that  of  any  other  metal  with  the  exception 
of  steel  and  iron,  great  resistance  to  corrosion  from  oxidation, 
and  qualities  of  ductility  and  malleability  that  make  it  easily 
worked;  it  has  a  fairly  low  temperature  coefficient  and  not 
being  subject  to  rapid  oxidation,  as  is  aluminum,  can  be  easily 
soldered. 

Copper  wire  is  usually  classed  in  two  grades,-  annealed  and 
hard  drawn,  which  differ  both  in  their  mechanical  and  their 
electrical  properties;  varying  with  the  size  of  the  conductor, 
annealed  solid  copper  wire  will  have  a  tensile  strength  of  from 
30,000  Ib.  to  42,000  Ib.  and  annealed  stranded  wire  of  from  29,000 
Ib.  to  37,000  Ib.  per  square  inch;  hard  drawn  will  run  from  45,000 
Ib.  to  68,000  Ib.  per  square  inch  for  the  solid  wire  and  from  43, 000 
Ib.  to  65,000  Ib.  for  the  stranded.  The  elastic  limit  for  solid 
annealed  copper  wire  is  6000  Ib.  to  16,000  Ib.  per  square  inch  and 
for  annealed  strand  from  5800  Ib.  to  14,800  Ib.;  for  hard-drawn 
solid  wire  it  runs  from  25,000  Ib.  to  45,000  Ib.  and  for  hard-drawn 
strand  from  23,000  Ib.  to  42,000  Ib.  per  square  inch,  as  given 
in  the  American  Steel  &  Wire  Company's  hand-book. 

There  are  intermediate  grades  of  hardness  and  strength,  such 
as  medium  hard  drawn,  which  are  sometimes  called  for  on 
account  of  a  desire  to  avoid  the  greater  liability  to  injury  through 
nicking  or  kinking  in  stringing,  to  which  the  hard  drawn  is  sus- 
ceptible; hard-drawn  wire  is  also  more  liable  to  break  in  time  at 
its  supports  where  it  is  tightly  clamped,  as  on  a  pin-type  insulator. 
The  conductivity  of  annealed  copper  wire  referred  to  Matthiessen's 
standard  is  from  99  per  cent,  to  102  per  cent.,  and  that  of  hard- 
drawn  wire  from  96  per  cent,  to  99  per  cent.,  as  ordinarily 

230 


STRINGING  WIRE  231 

given  by  wire  manufacturers;  the  temperature  coefficient  of 
linear  expansion  for  copper  wire,  per  degree  Fahrenheit,  is 
0.0000096. 

In  specification  for  transmission  copper  it  is  usual  to  call  for 
a  conductivity  of  not  less  than  98  per  cent,  for  annealed  or  soft- 
drawn  wire  and  not  less  than  97  per  cent,  for  hard-drawn,  based 
upon  Matthiessen's  standard. 

Annealed  wire  is  practically  never  used  nowadays  in  transmis- 
sion work,  and  for  conductors  larger  than  No.  4  B.  &  S.  it  is 
customary  to  employ  a  stranded  wire  on  account  of  the  greater 
ease  and  safety  in  handling,  and  greater  strength  than  that  of 
a  solid  wire  of  corresponding  section;  on  account  of  the  greater 
increment  in  the  base  price  of  seven-strand  over  that  of  three- 
strand  cable,  the  latter  is  sometimes  used  for  medium-size  con- 
ductors, due  consideration  being  also  given  the  fact  that  the 
individual  strands  become  quite  small  in  some  of  the  lighter 
seven-strand  conductors;  in  most  cases,  however,  depending 
upon  the  circular  mills,  either  seven-strand  or  nineteen-strand 
cables  are  used  for  the  conductor  sizes  required  in  transmission 
work. 

The  standard  method  of  making  up  strand  is  to  use  a  core 
wire  of  the  same  size  and  kind  as  the  other  strands,  but  in  many 
cases  a  hemp-center  cable  has  been  used  and  in  some  instances  a 
steel-core  wire;  the  object  of  the  hemp  center  is  to  place  all 
strands  under  equal  strain,  primarily,  though  the  reduction  of 
skin  effect  is  also  a  slight  factor,  while  the  use  of  a  steel  core 
is  prompted  by  a  desire  for  a  greater  total  breaking  strength. 

Aluminum  possesses  a  valuable  characteristic  for  line  purposes 
in  that  its  weight  for  the  same  conductivity  is  only  about  one- 
half  that  of  copper';  on  the  other  hand,  its  diameter  is  about 
1.37  and  its  area  about  1.64  times  that  of  copper  of  equal 
conductivity. 

The  main  features  that  have  deterred  engineers  from  using 
aluminum  to  a  great  extent  in  the  United  States,  however,  have 
been  partly  its  low  tensile  strength  and  high  coefficient  of  ex- 
pansion, which  required  careful  attention  to  the  stringing  of  a 
line  to  avoid  overstraining  at  maximum  load  conditions,  and 
partly  the  close  relationship  existing  between  the  aluminum 
and  the  copper  markets.  In  other  words,  there  has  never  been 
enough  economy  showTi  over  copper  to  warrant,  in  the  United 
States,  the  general  use  of  aluminum  with  its  requirements  of 


232  TRANSMISSION  LINE  CONSTRUCTION 

greater  care  and  more  exacting  allowances  of  sag.  The  fact 
also  that  some  trouble  was  experienced  in  the  earlier  days  of 
electrical  transmission  from  crystallization  of  aluminum  con- 
ductors, together  with  the  impossibility  of  making  splices  or 
connections  of  good  conductivity  in  the  manner  followed  in 
copper  work,  has  likewise  had  its  bearing  on  the  question;  with 
the  introduction  of  stranded  conductors  altogether  and  the  use 
of  sleeve  splices,  these  troubles  have  been  practically  eliminated, 
but  the  prejudice  has  not  altogether  been  removed. 

The  conductivity  of  aluminum  will  run  about  60  per  cent,  to 
63  per  cent.,  based  upon  Matthiessen's  standard,  being  given  as  62 
per  cent,  in  the  table  of  properties  issued  by  the  manufacturers. 
Its  tensile  strength  in  stranded  conductors  is  about  24,000  Ib. 
to  27,000  Ib.  per  square  inch,  with  an  elastic  limit  of  about 
14,000  Ib.  Comparing  hard-drawn  copper  and  aluminum  con- 
ductors of  the  same  conductivity,  and  basing  the  comparison 
upon  aluminum  having  about  60  per  cent,  the  conductivity  of  the 
hard-drawn  copper,  the  tensile  strength  of  the  aluminum  con- 
ductor is  only  about  65  per  cent,  of  that  of  the  copper  line  wire 
that  would  be  required  for  the  same  service. 

The  temperature  coefficient  of  linear  expansion  of  aluminum 
per  degree  Fahrenheit  is  0.0000130,  as  against  copper  at  0.0000096. 

Bi-metallic  wire,  describing  copper-clad  as  the  one  com- 
mercially available,  consists  of  a  steel  core  with  an  intimate 
covering  of  copper,  the  purpose  being  to  combine  the  strength  of 
steel  with  the  conductivity  and  non-corrosive  qualities  of  copper; 
its  greatest  field  has  been  in  telegraph  and  telephone  construc- 
tion, but  it  is  also  being  advocated  for  transmission  line  work, 
not  only  for  ground-wire  purposes,  but  for  conductors  also. 
Very  likely  it  will  work  out  well  for  conductor  purposes  in  the 
construction  of  light  lines,  where  with  the  use  of  long  spans,  it 
is  desirable  and  necessary  to  employ  conductors  of  greater 
strength  than  would  be  required  from  electrical  considerations 
alone. 

Attempts  were  made  over  forty  years  ago  to  effect  a  practicable 
combination  of  copper  and  steel  to  form  a  conductor  of  greater 
conductivity  than  steel  and  of  lesser  depreciation,  but  the  wire 
as  then  manufactured  did  not  hold  up  in  commercial  use,  being 
subject  to  rapid  corrosion  through  electrolytic  action;  with  the 
method  devised  by  Monot  of  effecting  a  weld  between  the  steel 
and  the  copper,  it  is  claimed,  and  the  claim  is  justified  by  its 


STRINGING  WIRE  233 

performance  in  practical  work,  that  copper-clad  wire  now  is 
a  commercial  success,  as  far  as  freedom  from  electrolytic  action 
is  concerned. 

As  given  by  Roebling,  bi-metallic  wire  has  a  tensile  strength 
about  25  per  cent,  greater  than  that  of  hard-drawn  copper,  and 
a  conductivity  about  65  per  cent,  of  that  of  pure  copper,  no  data 
being  given  as  to  the  relative  proportion  of  the  two  metals;  in 
the  Electrical  World  beginning  Dec.  22,  1910,  F.  F.  Fowle  pre- 
sents a  series  of  articles  bearing  upon  the  subject  of  compound 
wires,  giving  the  results  of  tests  and  investigations,  as  to  electrical 
properties  mainly;  in  his  articles  the  aluminum-coated  wire  has 
also  been  taken  up  though  this  is  not  as  yet  a  commercial  propo- 
sition. Mr.  Fowle  gives  for  No.  6  B.  &  S.,  with  a  core  diameter 
of  0.13  in.  and  a  shell  thickness  of  0.016  in.  a  conductance 
ratio  to  hard-drawn  copper  of  0.4408,  noting  that  the  rated 
ratio  for  this  wire  is  40  per  cent. 

Copper-clad  wire  has  been  employed  with  very  satisfactory 
results  for  ground-wire  purposes  in  place  of  steel,  as  under  the 
high  frequencies  to  which  it  is  subjected  in  lightning  protection 
it  presents  a  much  lower  impedance,  and  at  the  same  time  it 
possesses  the  mechanical  qualities  desirable. 

From  an  economical  standpoint,  for  general  use  as  a  line  con- 
ductor material  it  does  not  present  as  great  advantages  as 
might  be  expected,  the  price  of  No.  2  B.  &  S.  copper-clad  wire 
on  a  certain  job  being  13.5  cents  per  pound  while  No.  0  copper 
with  hemp  center  costs  17.7  cents  per  pound,  the  prices  being 
f.o.b.  the  job  in  each  case;  comparing  properties  and  cost  of 
this  wire  with  those  of  the  other  materials  and  taking  into  con- 
sideration the  scrap  value,  which  ought  also  to  have  a  bearing 
upon  the  matter,  it  would  appear  that  the  use  of  copper-clad 
for  conductor  purposes  will  be  limited,  in  the  case  of  average 
transmission  lines,  to  that  portion  of  the  work  where  extra  long 
spans  may  be  required,  though  for  light  lines  that  are  to  be 
carried  in  comparatively  long  spans  throughout  it  will  work  out 
economically;  it  will  also  of  course  have  a  place  in  telephone 
work,  where  the  telephone  line  is  carried  on  the  same  structures 
as  the  high-tension  wires. 

Steel  is  limited  in  use  for  energy  transmission  almost  entirely 
to  special  long-span  work,  such  as  is  encountered  in  river  cross- 
ings, etc.,  though  there  are  a  few  instances  where  it  has  been  used 
under  other  circumstances  in  important  work  on  account  of  its 


234  TRANSMISSION  LINE  CONSTRUCTION 

strength,  as  for  instance  the  2-mile  terminal  line  through  the 
city  of  Syracuse,  N.  Y.,  where  for  a  60,000-volt  single  circuit 
construction,  7/16-in.  galvanized  plough-steel  strand  was  used 
for  conductors.  It  has  also  been  employed  for  some  construction 
work  where  the  prime  requisite  was  cheapness. 

For  general  line  purposes,  outside  of  guying,  the  Siemens- 
Martin  grade  of  steel  strand  has  been  mostly  employed;  the 
conductivity  of  steel  strand  runs  from  8  per  cent,  to  11  per  cent, 
of  that  of  copper  and  its  coefficient  of  linear  expansion  per 
degree  Fahrenheit  is  0.0000064. 

Wire  for  transmission  line  work  is  usually  shipped  on  wooden 
reels,  but  in  the  smaller  sizes,  No.  10  to  No.  6,  such  as  may  be  re- 
quired for  the  telephone  line,  it  may  come  in  burlapped  coils. 
The  length  of  wire  per  reel  is  usually  specified  by  the  purchaser, 
not  limited  by  manufacturing  conditions,  and  depends  upon  the 
size  of  the  conductor,  the  topography  of  the  line,  the  method  of 
stringing  and  the  size  and  weight  of  the  reels  loaded;  in  medium 
sized  copper  strand,  lengths  of  from  1  mile  to  2  miles  per  reel  are 
common,  and  in  the  larger  sizes  from  3000  ft.  to  4000  ft.  per 
reel  is  often  specified. 

The  overall  diameter  of  reels  will  ordinarily  run  from  50  in.  to 
70  in.  with  an  outside  width  of  27  in.  to  33  in.,  giving  a  barrel 
diameter  of  from  24  in.;  to  30  in.  ordinarily  and  an  inside  width  of 
22  in.  to  28  in.  Reels  are  wound  so  as  to  leave,  when  fully  loaded, 
about  3  in.  or  so  of  clearance  between  the  cable  and  the  rim  of 
the  reel,  to  allow  of  their  being  rolled  in  handling,  without  danger 
of  injuring  the  wire;  ordinarily  the  cable  is  protected  by  a  layer 
of  tough  paper  and  a  covering  of  burlap,  but  where  hard-drawn 
copper  is  to  be  handled  through  rough  rocky  country,  it  is  often 
well  to  specify  that  the  reels  be  lagged. 

In  preparing  shipping  direction  for  wire,  especially  copper, 
not  only  should  convenient  locations  with  reference  to  the  line 
be  selected,  but  attention  should  be  given  to  ensuring  proper 
storage  facilities  upon  arrival;  copper  in  particular  is  a  commodity 
that  is  more  or  less  easily  convertible  into  cash,  and  it  is  just  as 
well  to  use  a  little  discretion  and  avoid  tempting  fate  by  provid- 
ing for  storage  space  in  a  warehouse  where  the  wire  can  be  kept 
under  lock  and  key. 

In  unloading  reels  from  the  cars  they  should  be  weighed  and 
the  weights  checked  against  those  billed,  noting  any  discrepancies 
or  any  indications  that  reels  have  been  disturbed;  if  it  is  not 


STRINGING  WIRE 


235 


possible  to  check  the  weights,  each  reel  should  at  least  be  given 
a  careful  inspection. 

When  the  crews  are  ready  to  begin  stringing  wire  the  reels 
should  be  hauled  out  and  left  at  farm-houses  as  close  as  possible 
to  the  points  where  the  material  will  be  needed;  the  reels,  set  on 
edge  and  solidly  blocked  in  the  box,  can  be  hauled*  out  in  ordinary 
farm-wagons;  the  cost  of  distribution  is  such  a  variable  quantity, 


FIG.  165. — Loading  reel  wagon. 


owing  to  the  fact  that  it  is  usually  not  hauled  directly  to  the 
place  where  it  is  to  be  used,  that  it  is  impossible  to  do  more  than 
to  approximate  it,  but  on  a  weight  basis  it  ought  not  to  exceed 
from  $1.75  to  $2.25  per  ton  delivered,  including  loading  at  the 
storehouse  and  unloading  at  destination,  with  figures  based  upon 
an  average  haul  of  5  miles  on  fair  country  roads  with  teams  at 
$4  per  ten-hour  day;  in  mountainous  or  rough  country,  the 
figures  w-ill  be  much  higher. 

Running-out,    stringing,    pulling-up,      and   tying-in   wire    is 


236  TRANSMISSION  LINE  CONSTRUCTION 

usually  carried  on  by  one  gang,  completing  the  erection  of  the 
wire  as  it  goes,  though  in  some  cases  the  wire  has  been  run  out 
and  carried  up  on  the  arms  by  one  gang  while  another  crew 
followed,  pulling-up  and  tying-in. 

Running  out  of  the  wire  may  be  done  by  mounting  the  reel  on  the 
axle  of  a  two-wheeled  reel  cart  and  uncoiling  the  wire  on  the  ground 
as  the  team  draws  it  along,  Figs.  165  and  166  showing  a  typical 
cart  of  this  kind;  or  the  reel  may  be  jacked  up  on  portable  frames 
and  held  immovable,  and  the  wire  run  out  by  hooking  a  team 
on  the  end  of  the  cable,  the  wire  being  carried  up  on  the  arms 
as  each  structure  is  reached  and  either  pulled  through  over  them, 
in  the  case  of  wooden  arms,  or  passed  through  snatch-blocks. 
With  pin-type  insulators,  the  wire  can  be  pulled  through  alright 


FIG.   166. — Reel  wagon. 

in  short  lengths  by  laying  it  in  the  wire  groove  of  the  insulator  or 
in  the  case  of  wooden  construction,  on  the  cross-arm,  but  this 
method  requires  care  and  is  not  as  satisfactory  as  the  use  of 
snatch-blocks.  The  use  of  reel  wagons  is  best  adapted  to  the 
stringing  of  medium  size  conductors  with  lengths  of  1  1/2  miles 
to  2  miles  of  wire  on  a  reel,  where  the  line  supports  are  close 
together,  and  where  pin-type  insulators  are  used;  where  suspen- 
sion-type insulators  are  employed  and  where  large  conductors 
with  short  lengths  of  cable  per  reel  are  to  be  strung  with 
supports  far  apart,  the  unreeling  and  stringing  from  fixed  reels 
will  usually  work  out  best. 

Where  reel  wagons  are  used  to  run  out  the  wire  for,  say  a 
single-circuit  line  with  a  ground  wire,  either  two  or  four  wagons 


STRINGING  WIRE  237 

will  be  used  simultaneously;  where  the  job  is  of  any  size  the 
use  of  four  wagons,  either  with  a  team  for  each  cart  or  with  two 
teams  taking  alternately  two  reels  a  mile  at  a  time,  is  advisable; 
the  teams  are  generally  placed  in  charge  of  a  handyman  or  a 
lineman  who  will  help  out  the  teamsters  as  needed,  clear  obstruc- 
tions from  the  path  of  the  teams,  open  fences  for  them,  etc. 

Following  the  teams  will  come,  in  the  case  where  two  teams 
are  used  alternately  with  two  sets  of  reel  wagons  and  the  "  going" 
is  fair,  a  crew  of  about  four  linemen  and  four  groundmen  in  charge 
of  the  crew  foreman;  this  crew  will  carry  the  wires  up  on  the  cross- 
arms,  the  teams  being  far  enough  ahead  so  that  all  the  wires 
on  the  structure  will  have  been  run  out  and  can  be  pulled  up  at 
one  climbing;  the  usual  method  of  pulling  a  wire  up  on  the  arm 
in  short-span  work  is  for  the  linemen  on  the  poles  attended  each 
by  a  groundman,  to  pull  it  up  hand  over  hand  with  a  hand  line, 
all  working  together;  in  long-span  construction  the  hand  line 
is  reeved  through  a  single-sheave  block  or,  in  the  case  of  a  heavy 
conductor,  a  pair  of  light  blocks  are  used,  and  the  groundmen 
hoist  the  wire  to  the  men  on  the  structure.  When  the  wire  is 
raised  up  on  to  the  structure  it  is  usually  laid  in  the  wire  groove 
of  the  insulator  in  the  case  of  the  pin  type,  or  is  placed  in  snatch- 
blocks  or  cable  rollers  in  the  case  of  the  suspension  type. 

Where  the  reels  are  set  on  stands  and  held  fixed  while  the  ends 
of  the  wires  are  drawn  out  by  a  team  usually  all  the  wires  on 
one  side  of  a  structure  are  run  out  at  the  same  time,  and  with 
some  little  trouble  wires  for  both  sides  of  the  supports  can  be 
drawn  out  simultaneously  with  one  team  by  unhooking  the  set 
for  one  side  at  each  support  and  passing  it  around  the  structure, 
using  a  sort  of  running  board;  this  is  liable  to  bring  injury  to  the 
wire,  delays  the  team,  requires  extra  men,  and  even  in  the  case 
where  the  total  number  of  wires  on  the  structures  is  only  four, 
it  is  doubtful  if  it  will  prove  as  economical  as  having  two  teams 
and  pulling  out  the  conductors  for  each  side  separately,  or  using 
one  team  and  working  one  side  at  a  time,  though  the  latter  will 
require  the  climbing  of  each  tower  twice. 

As  the  team  passes  each  tower  and  proceeds  far  enough  beyond 
to  give  a  little  slack,  the  wires  are  pulled  up  and  dropped  into 
snatch-blocks;  these  snatch-blocks,  in  the  case  of  suspension  in- 
sulators, are  supported  so  that  when  the  wire  is  in  them  it  will  be 
approximately  at  the  level  of  the  cable  clamps  on  the  insulator; 
as  noted  previously,  sometimes  in  wooden  pole  work  rollers  are 


238 


TRANSMISSION  LINE  CONSTRUCTION 


not  used,  the  wires  being  pulled  along  over  the  arms,  a  method 
that  should  not  be  used  for  stretches  of  any  length. 

When  about  a  mile  stretch  of  line,  or  a  reel's  length  if  less  than 
that,  is  run  out  and  hung,  the  crew  will  prepare  to  pull  up;  this 
is  done  either  by  the  same  men  who  have  been  hanging  the  wire 
up  or  by  another  section  of  the  crew,  depending  upon  the  rate 
of  speed  with  which  it  is  desired  to  carry  on  the  work. 

In  the  past  it  was  the  practice  to  pull  one  conductor  at  a  time, 
but  now  in  practically  all  work  it  is  customary  to  pull  all  three 

To  Come-a-longs  on  Line  Wires 

r 


To  Pulling  Blocks 
FIG.   167. — Equalizer  rig. 

of  the  wires  of  a  circuit  at  the  same  time,  the  same  tension  in 
each  being  insured  by  the  employment  of  an  equalizer.  This 
equalizer  consists  of  an  arrangement  of  single-sheave  blocks 
reeved  as  shown  in  Fig.  167,  and  connected  to  an  equalizer  bar 
of  oak,  4  in.  X  6  in.  in  section  or  of  any  other  size  that  may  be 
required;  to  the  hook  of  each  of  the  three  " floating"  single- 
sheave  blocks  is  attached  a  wire  grip,  and  with  these  each 
clamped  to  its  wire,  it  is  obvious  that  as  tension  is  applied  to  the 


STRINGING  WIRE  239 

system  by  means  of  the  main  pulling  blocks,  any  inequalities 
in  the  lengths  of  these  three  wires  will  be  adjusted  by  the  move- 
ment of  the  floating  single-sheave  blocks,  so  that  all  wires  will 
be  pulled  up  under  the  same  tension.  An  arrangement  similar 
to  the  above,  using  three  single-sheave  blocks  with  a  three- 
sheave  block  in  place  of  the  bar,  is  also  used,  but  is  hard  to  rig 
and  hard  to  keep  from  fouling,  the  arrangement  described  being 
preferable;  it  is  evident  that  by  the  use  of  additional  blocks, 
these  schemes  can  be  adapted  to  the  simultaneous  pulling  up  of 
any  reasonable  number  of  wires. 

With  the  line  wires  spliced  at  the  far  end,  the  general  routine  of 
pulling  up  is  as  described  in  the  following,  the  work  being  out- 
lined for  a  wooden  pole  line  in  particular  though  necessarily 
the  same  applied  to  any  kind  of  construction. 


To  Team 


FIG.  168. — Pulling  up  wire. 

Referring  to  Fig.  168,  A  is  the  last  pole  upon  which  the  wires 
have  been  carried;  the  pulling  blocks  are  first  hooked  into  a 
sling  about  the  butt  of  B,  the  next  pole  ahead  and  extended 
about  50  ft.  or  60  ft.,  these  blocks  being  8-in.  three  sheave  and 
reeved  with  7 /8-in  or  1-in.  line  for  average  work;  next  the  pull- 
ing grips  fastened  on  the  floating  equalizer  blocks  are  slipped 
on  to  their  individual  wires,  the  equalizer  bar  carried  back  and 
the  pulling  blocks  hooked  into  the  clevis  of  the  bar;  tfyen  a  team 
is  hooked  on  to  the  fall  line  of  the  blocks  and  the  wires  are  drawn 
to  the  proper  tension,  or  a  pair  of  luff-blocks  may  be  used  in  place 
of  the  team;  when  the  wires  have  been  pulled  to  the  required 
tension  or  sag,  the  determination  of  which  is  discussed  later  in 
the  chapter,  the  fall  line  is  snubbed  and  a  head  guy,  either  of 
rope  or  a  piece  of  guy  strand  is  run  from  the  top  of  pole  A  to 
the  butt  of  B;  with  this  head  guy  in  place,  a  lineman  climbs  pole 
.1  with  a  wire  clamp  or  grip  for  each  wire.  He  first  fastens 
each  grip  to  the  cross-arm  by  means  of  a  rope  sling,  and  then 
reaches  out  and  slides  the  grip  out  in  place  on  the  wire  so  that 


240  TRANSMISSION  LINE  CONSTRUCTION 

upon  slightly  slacking  off  the  pulling  blocks  these  snub-grips 
or  holding-come-a-longs  take  the  strain,  making  a  dead-end 
pole  temporarily  out  of  pole  A;  the  men  now  go  back  and  tie 
in  the  stretch  pulled  up  and  then  go  ahead  again  hanging  up  the 
wire  and  preparing  the  next  mile  stretch  for  pulling,  the  holding 
grips  and  head  guy  being  of  course  left  on  A  until  the  next  pull 
is  made  and  held.  In  tower  work  the  method  is  the  same, 
except  that  there  are  no  handy  snubbing  poles  and  stakes  must 
generally  be  driven  for  the  pulling  blocks;  under  the  weather 
conditions  usually  prevailing  when  wire  is  strung,  in  most 
cases  towers  will  not  require  head-guying  to  hold  the  temporary 
dead-end,  though  where  tower  anchors  have  been  newly  set, 
it  is  often  better  to  be  on  the  safe  side. 

The  grips  or  wire  clamps  used  should  preferably  be  of  the 
parallel-jaw  type,  similar  to  the  Buffalo  grip,  for  general  work. 

The  splicing  of  line  conductors  of  any  of  the  materials  is  pref- 
erably done  with  sleeving,  though  in  the  case  of  copper  very 
satisfactory  results  can  be  obtained  from  the  use  of  the  "  sun- 
burst" or  cable  splice  for  strand,  and  a  modified  Western  Union 
for  solid  wire;  the  danger  of  injury  in  making  up  these  splices 
where  hard-drawn  wire  is  used,  together  with  the  longer  time 
required  for  the  making  of  a  joint  and  the  fact  that  as  good  an 
electrical  connection  is  not  secured,  usually  makes  the  use  of 
sleeve  splices  an  economical  consideration. 

In  making  up  sleeve  splices,  from  three  and  one-half  to  four 
complete  turns  should  be  taken  and  the  twisting  should  be  done 
from  both  ends,  care  being  taken  not  to  split  the  sleeve  or  nick 
the  conductor;  where  sleeves  are  made  with  a  joint,  care  should 
be  taken  to  see  that  they  do  not  open  up  at  this  point.  The 
twisting  should  be  done  with  special  tools  and  the  connectors 
or  splicing  clamps  for  this  purpose  should  be  made  heavy  enough 
to  stand  the  work  without  springing,  should  fit  snugly  to  the 
sleeve  end,  and  should  be  made  with  a  long  enough  leverage 
so  that  the  maximum  size  of  sleeve  for  which  they  are  intended, 
can  be  made  up  with  ease.  There  are  several  types  of  clamps 
supplied  by  sleeve  manufacturers,  some  of  them  made  for  use  on 
three  or  four  sizes  of  sleeve  by  means  of  a  rotating  jaw  on  one  side, 
which  have  to  the  writer's  knowledge  been  so  inadequate  that 
the  splicers  preferred  to  use  two  monkey  wrenches  set  up  tight; 
in  place  of  them. 

In  the  making  of  the  "  Sunburst "  or  cable  splice,  the  length  of 


STRINGING  WIRE  241 

the  completed  joint  should  be  from  thirty  to  forty  times  the 
diameter  of  the  conductor;^  the  strands  at  the  neck  or  the  point 
of  interlacing,  should  be  laid  as  straight  and  as  smoothly  as 
possible  avoiding  all  kinks,  and  the  serving  should  be  done 
without  nicking  the  strands  or  the  conductor.  In  the  making 
up  of  Western  Union  joints  not  much  of  an  attempt  has  evidently 
been  made  to  secure  the  best  possible  results  from  that  type  of 
connection,  and  we  find  joints  that  are  both  mechanically  and 
electrically  weak;  rough  comparative  tests  made  by  the  writer 
in  corroboration  of  the  tests  on. iron  wire  joints  published  in  the 
Electrical  World  for  Nov.  17,  1910,  make  it  clear  that  a  very 
good  mechanical  splice  of  the  Western  Union  type  can  be  made 
in  copper  by  giving  from  five  to  six  complete  turns  in  the  "  neck" 
of  the  joint  with  about  three  short  close  turns  at  each' end;  in 
the  tests  of  iron  wire  in  the  smaller  sizes  cited  above,  it  was  found 
that  five  turns  in  the  neck  of  the  joint  would  give  it  a  breaking 
strength  equal  or  better  than  that  of  the  wire. 

In  general,  there  is  usually  no  trouble  in  making  up  test  speci- 
mens of  splices  that  will  develop  the  full  strength  of  the  cable, 
but  the  matter  of  insuring  the  same  standard  in  the  field  will 
require  skilled  splicers  and  close  inspection;  in  this  regard  the 
sleeve  joint  lends  itself  to  a  greater  uniformity. 

The  writer  once  had  occasion  to  make  a  few  tests  of  the  ordi- 
nary joints,  sleeve,  "Sunburst/7  and  Western  Union,  as  made 
up  by  average  linemen  in  the  field;  the  tests  were  made  in  a 
standard  testing  machine  and  are  interesting.  The  first  joint 
was  a  7-in.  sleeve  splice  in  No.  5  hard-drawn  copper  with  about 
three  and  one-half  turns;  this  stood  the  pull  without  any  apparent 
slipping  until  650-lb.  load  was  applied,  whereupon  the  wire 
pulled  through  a  little,  the  failure  taking  place  at  about  800 
Ib.  outside  the  sleeve  where  the  wire  slipped  through  the  sleeve 
had  straightened  out;  a  Western  Union  joint  in  No.  5  hard-drawn 
wire  failed  at  610  Ib.  slipping  considerably  before  breaking;  this 
joint  was  made  up  with  about  two  and  one-half  to  three  turns 
in  the  "neck"  and  three  to  four  end  turns,  being  about  7  in. 
overall. 

In  a  comparison  of  the  strengths  of  sleeve  and  "  Sunburst " 
splices  in  No.  2  copper  strand,  the  former  broke  at  2760  Ib., 
failing  at  a  point  just  outside  of  the  end  of  the  sleeve,  and  the 
latter  at  the  middle  of  the  joint  where  the  interlacing  takes 

16 


242  TRANSMISSION  LINE  CONSTRUCTION 

place,  at  3000  Ib.,  the  strand  itself,  No.  2  nominal,  made  up  of 
seven  strands  of  No.  10  B.  &  S.,  broke  at  3310  Ib. 

It  will  be  noted  that  these  tests  are  not  necessarily  representa- 
tive of  splices  in  general,  being  merely  made  for  information  in  a 
certain  case;  it  may  be  also  noted  that  the  sleeves  used  were  of 
the  seam  type  and  that  they  split  easily  so  that  the  linemen 
rather  undertwisted  them  in  most  cases. 

The  labor  cost  of  making  splices  will  vary  from  a  few  cents  up 
to  $1.50  or  more,  depending  upon  the  size  of  the  conductors 
and  the  kind  of  splice;  sleeves  themselves  will  run  10  cents  to 
$1  for  the  sizes  called  for  in  average  line  work.  Copper  sleeves 
are  used  for  copper  and  for  steel  wires,  being  made  of  greater 
thickness  and  tinned,  where  used  for  steel;  Aluminum  conductors 
require  a  sleeve  of  that  material. 

In  heavy  construction  work  where  the  larger  sizes  of  conduct- 
ors in  short  lengths  are  used,  a  lineman  with  a  helper  will  be 
steadily  employed  at  splicing  and  if  the  conductors  be  unusually 
large  he  may  require  two  men;  where  the  conductor  is  medium 
size  and  comes  in  long  lengths  with  few  field  cuts  required,  two 
of  the  men  in  the  stringing  gang  can  be  used  for  the  making  up 
of  joints,  working  with  the  main  gang  otherwise. 

The  deflection  or  sag  allowed  for  similar  lines  under  identical 
weather  conditions  varies  in  about  the  same  way  as  the  assump- 
tions as  to  the  extreme  load  for  which  towers  should  be  designed. 
It  is  not  within  the  scope  of  this  work  to  consider  the  various 
methods  of  calculation,  but  in  passing  the  writer  may  note  that 
for  one  particular  job,  where  a  seven-strand  cable  a  little  larger 
than  No.  2  B.  &  S.  was  to  be  strung  in  500-ft.  spans,  recommenda- 
tions from  three  engineers  as  to  the  sag  to  be  given  at  a  certain 
temperature  were  respectively,  11  ft.,  20  ft.,  and  27  ft. 

The  standard  maximum  loading  for  the  calculation  of  deflec- 
tion as  now  recommended  by  the  leading  engineering  societies 
is  a  1/2-in.  coating  of  sleet  all  around  the  conductor,  with  a  wind 
pressure  of  8  Ib.  actual  per  square  foot  of  the  projected  area  of  the 
sleet-covered  conductor,  the  sag  to  be  such  that  with  this  load 
the  tension  in  the  cable  will  be  less  than  its  elastic  limit  if  the 
temperature  drops  to  zero  degrees  Fahrenheit,  or  as  it  is  some- 
times specified,  the  wire  is  to  have  a  factor  of  safety  of  two  at 
this  load  and  temperature.  This  standard  assumption  of  maxi- 
mum loading  should,  of  course,  be  used  with  discretion  as  there 
are  some  localities  where  it  may  be  exceeded,  and  a  great  many 


STRINGING  WIRE  243 

where  it  will  never  occur;  a  study  of  Weather  Bureau  records 
will  enable  the  engineer  to  determine  his  particular  conditions 
and  govern  his  assumptions  accordingly;  it  is  certain  that  a 
large  percentage  of  the  transmission  lines  in  the  Middle  West 
have  not  been  strung  in  accordance  with  a  loading  as  heavy  as 
the  one  quoted,  and  it  takes  lots  of  mental  suasion  and  a  few 
cuss  words  to  make  some  of  the  old-time  line  foremen  understand 
the  necessity  of  giving  even  the  deflections  that  have  been  allowed. 

For  methods  of  computing  sag,  the  reader  is  referred  to  the 
article  by  Mr.  Blackwell  in  the  1904  Transactions  of  the  Inter- 
national Electrical  Congress  and  to  those  by  Mr.  Robertson, 
Mr.  Thomas,  and  Messrs.  Fender  and  Thompson  in  the  1911 
Transactions  of  the  American  Institute  of  Electrical  Congress. 

For  the  guidance  of  the  construction  foreman,  a  curve  or  a 
table  giving  the  sag  or  tensions  at  various  temperatures  for  the 
standard  length  of  span,  should  be  made  up. 

In  pulling  up  wire,  most  companies  now  use  a  dynamometer, 
a  heavy  spring  scale,  to  measure  the  tension  exerted,  but  the 
general  method  followed  in  the  past  has  been  to  sight  for  the 
deflection;  where  this  method  is  used  a  man  is  stationed  up  on 
a  pole  or  tower,  at  about  the  middle  of  the  section  being  pulled, 
with  his  eye  at  a  distance  below  the  conductor  support  equal 
to  the  desired  deflection,  and  as  the  wire  is  drawn  up  he  lines  in 
the  low  point  of  the  sag  with  a  mark  at  the  same  point  on  the 
next  structure;  while  the  general  custom  is  to  take  these  refer- 
ence points  on  part  of  the  structures  themselves,  the  better  way  is 
to  make  up  two  rods  marked  off  in  feet  and  tenths  and  provided 
with  some  sort  of  a  movable  target  or  indicator  similar  to  a 
level  rod;  these  rods  can  be  arranged  to  hang  from  the  conductor 
support  or  some  other  desirable  place,  and  by  means  of  the 
targets  closer  results  can  be  obtained  than  are  possible  where 
points  on  the  structures  themselves  are  assumed. 

For  accurate  results,  however,  in  modern  long-span  work 
especially,  a  dynamometer  should  be  employed  and  the  wires 
drawn  up  to  the  actual  tension  required  for  the  particular  span 
at  the  existing  temperature;  where  all  three  wires  of  a  circuit 
are  pulled  at  the  same  time  with  an  equalizer  as  described  earlier 
in  the  chapter,  it  is  sufficient  to  use  a  dynamometer  in  one  leg 
only,  as  the  tensions  will  adjust  themselves  equally. 

The  sags  in  all  the  spans  will  also  adjust  themselves  ordinarily 
and  take  the  same  relative  deflections  as  the  span  sighted,  or  in 


244 


TRANSMISSION  LINE  CONSTRUCTION 


the  case  of  wires  pulled  to  a  certain  tension  will  take  practically 
uniform  sags  corresponding  to  the  tension;  where  long  lengths 
of  line  are  pulled  and  no  rollers  or  blocks  are  used,  it  is  well  to 
leave  the  strain  on  for  fifteen  or  twenty  minutes  before  beginning 
to  tie  in. 

Tying  in  or  fastening  wires  to  their  insulators  is  accom- 
plished either  by  the  use  of  tie  wires  or  some  form  of  clamp  arrange- 
ment; in  most  cases  with  pin-type  insulators  wire  ties  have  been 
used,  but  for  the  suspension  type,  clamps  are  invariably  employed 
for  transmission  work. 

In  Fig.  169  is  shown  a  method  of  wire  tying  that  has  been  used 
very  extensively  and  has  always  been  satisfactory;  in  tying  by 


FIG.  169. — Common  high  tension  tie. 


FIG.  170. — Figure  8  tie. 


this  method,  standing  facing  in  a  direction  at  right-angles  to  the 
line,  the  tie  wire  is  bent  into  the  shape  of  a  long  narrow  "  U  " 
and  pulled  in  from  the  back  of  the  insulator  so  that  the  bottom 
of  the  "U"  rests  in  the  tie-wire  groove  and  the  sides,  coming 
below  the  conductor,  extend  toward  the  man  tying;  then  the 
ends  or  sides  of  the  "U"  are  brought  up  and  over  the  conductor 
so  as  to  take  one  turn  around  it  on  each  side  of  the  head  of 
the  insulator,  which  brings  the  ends  back  in  order  to  point  at  the 
workman  as  before;  then  the  tie  ends  are  each  brought  around 
the  front  of  the  head  to  the  opposite  side  of  the  insulator,  in  the 
tie  groove,  under  the  conductor  in  each  case  and  then  around 
and  served  out  as  shown  in  the  illustration. 


STRINGING  WIRE 


245 


FIG.   171. — Mershon  tie. 


FIG.   172. — Kern  River  tie. 


FIG.  173. — Angle  tie. 


246  TRANSMISSION  LINE  CONSTRUCTION 

In  Fig.  170  is  shown  another  tie,  known  as  the  "figure-8," 
where  the  tie  is  begun  by  having  the  middle  of  the  tie  wire  at 
the  center  of  the  insulator  head  and  then  bringing  the  ends 
down  into  the  tie-wire  groove  on  opposite  sides  of  the  conductor, 
coming  back  under  the  conductor  on  each  side,  and  around  the 
head  to  the  opposite  side,  where  it  is  served  out  as  shown;  the 
claim  for  this  tie  is  that  the  cross-over  at  the  top  helps  to  bind 
the  conductor  and  prevents  slipping.  The  writer's  personal 
experience  with  this  kind  of  a  tie  has  not  been  very  satisfactory, 
as  with  standard  insulators,  it  has  been  found  to  work  loose; 
where  the  insulator  has  a  deep  tie-wire  groove  and  is  well  re- 
cessed at  the  ends  of  the  conductor  groove,  with  careful  attention 
to  the  bringing  of  the  tie  from  the  top  cross-over  of  the  head  into 
the  side  groove,  this  tie  will  work  out  well,  and  it  has  been  found 


F.IG.   174. — Clark  line  clamp.  FIG.   175. — Clark  angle  clamp. 

satisfactory  in  several  installations.  With  the  tie  just  described, 
a  shorter  length  of  tie  wire  is  necessary  than  in  the  case  of  the 
one  first  noted. 

In  the  Niagara,  Lockport  &  Ontario  transmission  work,  a 
double-loop  tie,  as  shown  in  Fig.  171,  was  employed,  a  tie  wire 
being  looped  around  the  head  of  the  insulator  in  each  direction 
and  the  double  ends  served  out  together;  the  advantages  of  this 
tie  as  noted  by  Mr.  Mershon  in  the  1907  Transactions  of  the 
American  Institute  of  Electrical  Engineers  on  page  1297,  are 
that  the  full  strength  of  the  tie  wire  is  developed  and  that  it 
does  not  injure  the  soft  aluminum  cable  as  other  types-  of  ties 
would. 


STRINGING  WIRE  247 

A  tie  such  as  shown  in  Fig.  172,  used  in  the  Kern  River  trans- 
mission work  and  also  on  the  lines  in  connection  with  the  Roose- 
velt Dam  Reclamation  project,  is  very  similar  to  the  tie  just 
described  except  that  the  ends  of  the  loop  are  secured  by  special 
clamps  instead  of  being  served  out  on  the  conductor. 

For  angle  or  corner  work;  the  conductor  is  tied  in  on  the  out- 
side of  the  insulator  with  what  is  known  to  telephone  men  as  a 
"copper"  or  "long-distance"  tie;  this  tie  is  shown  in  Fig.  173, 
and  the  writer's  experience  with  it  both  on  hard  drawn  and  soft 
wire  has  been  very  satisfactory. 

Wire  ties  for  copper  conductors  should  be  of  annealed  copper 
and  for  aluminum,  should  be  a  soft  wire  of  that  metal;  the  size 
of  the  tie  wire  will  depend  upon  the  gage  of  the  line  wires  and 


FIG.  176. — Suspension  insulator  clamp. 

the  type  of  tie  used,  but  as  a  general  thing  from  No.  8.  to  No.  4 
ties  will  be  used  in  average  work. 

Mechanical  clamps  in  the  place  of  wire  ties,  have  been  used 
extensively,  such  as  those  manufactured  by  the  Clark  Electrical 
&  Manufacturing  Company  shown  in  Figs.  174  and  175;  the 
employment  of  mechanical  clamps  is  often  specified  by  railroads 
for  high-tension  crossings;  as  will  be  noted  they  are  made 
for  both  straight  line  and  angle  work.  On  some  work  a  type 
of  mechanical  clamp  has  been  used  consisting  of  a  cast-iron  cap 
cemented  over  the  head  of  the  insulator,  to  which  is  bolted  a 
cover  plate,  the  cap  and  plate  being  provided  with  a  groove  in 
which  the  conductor  is  clamped. 

For  fastening   conductors   to   pin-type  insulators   on   strain 


248 


TRANSMISSION  LINE  CONSTRUCTION 


towers,  with  two  or  more  insulators  in  series,  either  a  loop  and 
clamp  arrangement  similar  to  the  tie  shown  in  Fig.  172,  only 
heavier,  or  a  yoke  connecting  the  head  of  the  insulators  together 
so  as  to  divide  the  strain  equally  between  them,  is  used,  the  con- 
ductors being  clamped  to  this  yoke;  an  arrangement  of  this 
kind  is  illustrated  in  Fig.  138. 


FIG.  177. — Suspension  insulator  clamp. 

A  conductor  is  usually  dead-ended  on  pin-type  insulators  by 
making  a  "  figure  8";  this  consists,  in  the  case  of  a  two-pin  dead- 
end, in  taking  a  turn  around  the  head  of  the  first  insulator,  then 
going  back  to  the  next  one  and  taking  a  turn  around  that  in  the 


FIG.   178. — Suspension  insulator  clamp. 

reverse  direction,  bringing  the  end  back  to  the  front  insulator 
on  the  opposite  side  from  which  it  left;  the  end  is  then  either 
served  up  or  fastened  with  a  clamp  in  the  same  manner  as  a 

guy. 

For   the   attachment   of  line   conductors   to   suspension-type 
insulators    various    designs    of    clamps    have    been    developed; 


STRINGING  WIRE 


249 


typical  kinds  furnished  by  representative  insulator  manufac- 
turing companies  for  straight  line  and  for  strain  service,  are  shown 
in  Figs.  176,  177,  178,  179,  and  180. 

The  features  that  a  clamp  for  this  purpose  should  have,  are 
those  of  a  broad  enough  bearing  area  so  as  not  to  injure  tne  con- 
ductor, a  curved  wire  groove,  flared  slightly  at  the  ends,  and  a 


FIG.   179. — Strain  insulator  clamp. 

short,  freely  moving  connection  to  the  insulator  to  avoid  kinking 
when  insulators  are  deflected  on  account  of  unequal  temperature 
changes  in  adjacent  spans;  a  clamp  should  also  be  designed  with 
as  few  parts  as  possible,  and  be  so  arranged  as  to  permit  the 
conductor  to  be  supported  by  it  before  the  clamping  is  applied. 
In  all  cases  where  aluminum  wire  is  used,  a  protecting  sleeve 


Fie.   180. — Strain  insulator  clamp. 

of  the  same  metal,  about  1/16  in.  in  thickness,  is  slipped  over  the 
conductor  at  the  point  of  clamping,  and  in  several  cases  the  same 
protection  has  been  used  on  copper  lines. 

For  the  attachment  of  ground  wires  to  a  structure,  either  a 
flat  clamp  or  a  U-bolt  arrangement  is  generally  used,  though  in 
wooden  pole  construction  a  pin  support  provided  with  a  pony 


250  TRANSMISSION  LINE  CONSTRUCTION 

insulator  has  been  employed  in  some  cases;  the  flat-plate  clamp 
is  preferable  to  a  U-bolt,  as  the  latter  is  more  liable  to  cut  the 
ground  wire  in  time;  in  tower  work  a  plate  clamp  is  generally 
supplied,  though  in  some  instance  in  lieu  of  the  same,  the  top 
casting  of  the  tower  was  provided  with  a  head  and  groove  to 
which  the  ground  wire  was  tied  in  with  a  regular  insulator  tie. 

Where,  in  the  case  of  wooden  pole  construction,  it  is  neces- 
sary to  run  a  tap  to  ground  from  the  top  of  the  pole,  a  No.  6 
or  No.  4  copper  wire  should  ordinarily  be  used,  though  heavy 
galvanized  iron  wire  has  been  employed  in  some  instances; 
this  is  either  bolted  in  under  the  ground  wire  clamp  or  served 
out  on  the  wire  itself  where  a  pin  and  insulator  support  is  used 
for  the  ground  wire,  and  then  brought  down  the  pole,  stapled 
every  2  ft.  or  3  ft.;  in  driving  the  staples,  care  should  be  taken 
not  to  kink  or  cut  the  wire.  In  the  case  of  steel  structures  set 
in  concrete,  a  copper  wire  is  usually  clamped  to  one  or  two  of  the 
corner  posts  inside  the  footing,  and  brought  out  to  the  ground. 

The  grounding  is  accomplished  by  driving  a  3/4-in.  or  1-in. 
galvanized  pipe  into  the  ground,  by  burying  a  copper  or  a  gal- 
vanized iron  plate,  by  the  use  of  some  one  of  the  patent  grounds, 
or  by  making  a  coil  of  a  few  turns  of  the  ground  tap  and  dropping 
it  into  the  bottom  of  the  hole  as  the  pole  is  set;  of  these  the 
first  two  mentioned  are  the  ones  that  are  best  adapted  to  trans- 
mission line  work;  the  use  of  a  small  coil  of  wire  does  not  give 
much  contact  area  and  is  of  questionable  value  for  this  particular 
purpose  also,  inasmuch  as  the  impedance  offered  to  a  high 
frequency  current  must  be  greater  than  that  of  the  other  types. 

The  pipe  ground  is  the  most  economical  to  install  and  allows 
inspection  the  most  readily;  as  ordinarily  used  it  consists  of  a 
length  of  pipe  from  7  ft.  to  15  ft.  long  driven  into  the  ground 
as  closely  into  the  butt  of  the  pole  as  possible,  the  shorter  length 
of  pipe  being  employed  where  the  top  of  the  pipe  is  driven  flush 
with  the  ground  and  the  longer  where  it  is  desirable  to  bring  the 
connection  of  the  ground  tap  to  the  pipe  at  a  point  where  it  can- 
not be  injured,  as  might  occur,  and  does,  where  the  pipe  is  driven 
flush  with  the  ground  in  tilled  land.  The  connection  of  the  tap 
to  the  pipe  may  be  made  by  soldering  it  down  the  side  of  the 
pipe  for  a  few  inches  or  to  a  cap  screwed  on  top,  or  by  stuffing 
a  piece  of  waste  down  into  the  pipe  so  as  to  bring  the  top  of  it 
about  3  in.  or  4  in.  down,  placing  the  wire  inside,  with  its  end 
doubled  back  several  times,  and  filling  with  solder. 


STRINGING  WIRE  251 

Considering  the  work  of  stringing  wire  as  a  whole,  the  size 
of  the  crew  that  will  be  required  will  depend  upon  the  number 
of  wires,  their  size,  the  length  of  span,  the  type  of  insulator 
and  the  voltage,  the  character  of  the  country,  the  total  amount 
of  work,  and  the  design  and  arrangement  of  the  supports;  for 
average  work  the  wire  gang  will  run  from  ten  to  twenty-five 
men  with  from  one  to  five  teams.  The  proportion  of  linemen  to 
groundmen  depends  upon  the  character  of  the  construction,  but 
as  a  general  thing  about  half  the  men  are  linemen,  though  some 
tower  work  has  been  done  complete  without  the  use  of  anything 
but  ordinary  unskilled  labor.  The  cost  per  mile  of  wire  for 
stringing  complete  will  run  from  $6  to  $30  for  sizes  from  No.  10 
B.  &  S.  to  250,000  circ.  mil  copper;  where  single-circuit  line  is 
strung  the  cost  is  higher  per  mile  of  wire  than  where  the  con- 
struction is  double  circuit. 

On  an  11,000-volt,  single-circuit,  steel  pole  job  in  Colorado, 
where  the  supports  averaged  35  ft.  in  overall  length,  the  con- 
tract price  for  stringing  No.  3  B.  &  S.  copper  was  $50  per  mile 
of  line  or  $16.67  per  mile  of  wire. 

On  another  job,  a  double-circuit  steel  tower  line  in  Utah, 
carrying  two  ground  wires,  six  No.  0  B.  &  S.  hard-drawn  copper 
strand,  and  two  telephone  wires,  the  cost  of  stringing  per  mile 
of  line  was  $43  for  the  ground  wires,  $94  for  the  conductors, 
and  $27.50  for  the  telephone  circuit,  or  per  mile  of  wire,  re- 
spectively $21.50,  $15.66  and  $13.75;  this  is  a  45,000-volt  line 
carried  on  45-ft.  towers  in  500-ft.  spans,  two  unit  suspension- 
type  insulators  being  used.  The  wage  scale  averaged  about 
30  per  cent,  to  40  per  cent,  higher  than  that  in  the  East  or  the 
Middle  West. 

The  erection  of  No.  2  stranded  copper  on  a  single-circuit  and 
ground,  40-ft.  wooden  pole  line  in  the  Middle  West  using  60,000- 
volt  pin-type  insulators,  was  about  $12  per  mile  of  wire,  with 
linemen  at  $2.75,  groundmen  at  $2  and  teams  at  $4  a  day. 

In  the  Sanitary  District  work,  the  cost  of  stringing  wire  on 
the  60-ft.  overall  steel  poles  is  given  at  $26  per  mile  of  conductor; 
270,000  circ.  mil  aluminum  wire  was  used  and  the  work  was  done 
by  contract. 

The  Electrical  World  for  Sept.  9,  1911,  gives  the  cost  of  wire 
stringing  on  the  Amherst  Power  Company  job,  as  $145  per  mile 
of  line;  this  is  a  single  circuit  line  of  No.  2  copper,  with  a  ground 
wire  of  7/16-in.  steel  and  two  telephone  wires  of  1/4-in.  steel, 


252  TRANSMISSION  LINE  CONSTRUCTION 

a  total  of  six  wires;  averaging  the  six  wires  as  being  the  same, 
the  cost  per  mile  of  wire  will  be  $24.16,  or  we  may  say  about 
$25  per  mile  for  the  conductors;  this  line  is  only  8.5  miles  long, 
one  power  wire  was  threaded  through  the  structure,  and  the  work 
was  done  by  contract;  the  towers  are  45-ft.  standard  with  60,000- 
volt,  pin-type  insulators. 

In  the  line  construction  of  the  Ontario  Hydro-Electric  Power 
Commission's  110,000-volt  system,  the  cost  of  stringing  ground 
wires  and  conductors  on  the  double-circuit  construction  is  given 
in  the  Electrical  World  for  Jan.  13, 1912.,  as  $130  per  mile  average; 
the  conductors  are  No,  000  and  No.  0000  aluminum  and  the 
ground  wires,  of  which  three  were  strung  on  the  double-circuit 
towers,  are  5/16-in.  steel  strand,  and  the  average  cost  per  mile 
of  wire  strung,  figuring  the  power  and  the  ground  cables  roughly 
on  the  same  basis,  is  $14.44.  In  the  single-circuit  work  where 
three  No.  000  aluminum  cables  and  two  ground  wires  were 
strung,  the  average  cost  per  mile  of  line  is  given  as  $80  or  aver- 
aging on  the  same  basis  as  before,  is  $16  per  mile  of  wire. 


CHAPTER  XII 
COST  DATA  FOR  TYPICAL  TRANSMISSION  LINES 

Much  difficulty  is  encountered  in  securing  accurate  cost 
figures  of  transmission  line  construction,  with  information  as  to 
conditions  obtaining  during  the  course  of  the  work,  the  wage 
scale,  etc.,  and  often  what  little  is  given  out  may  be  hedged  in 
with  conditions  so  as  to  make  it  valueless.  The  costs  given 
herein  are  bona  fide  figures  which  are  noted  without  any  attempt 
to  make  undue  comparisons  or  criticisms,  the  desire  being  merely 
to  include  and  call  attention  to  all  features  making  for  an  un- 
usually high  or  an  extra  low  cost  figure. 

We  may  begin  with  a  light  13,200-volt  line,  interesting  to 
many  because  many  lines  of  this  moderately  low-voltage  con- 
struction are  being  built,  following  the  general  tendency  to  con- 
nect the  smaller  villages  with  the  large  towns. 

This  line  is  built  in  Iowa  with  6-in.  top,  30-ft.  northern  cedars 
as  standard,  set  with  a  standard  spacing  of  135  ft.;  a  few  poles 
are  of  greater  length,  some  up  to  50  ft.,  and  some  of  the  poles 
are  7-in.  top;  the  butts  of  the  poles  were  treated;  the  digging 
was  fair  as  the  soil  was  average  loam.  The  pole  top  has  one 
wire  at  the  top  mounted  on  a  malleable  iron,  pole-top  pin,  with 
the  other  two  wires  carried  on  a  two-pin  36-in.  standard  arm 
below,  to  give  a  triangular  conductor  spacing;  the  cross-arm 
pins  are  of  wood,  11  in.  Xl  1/2  in.,  and  the  insulators  are  Locke 
No.  2643.  The  three  line  wires  are  No.  6  B.  &  S.  bare  copper; 
the  total  length  of  line  is  7  1/2  miles. 

The  total  cost  complete  is  given  as  $625.82  per  mile,  and  this 
figure  includes  $20  per  mile  for  tree  trimming;  it  may  also  be 
noted  that  this  line  w^as  originally  built  single-phase  and  the 
third  wire  run  in  afterward,  which  would  naturally  bring  the 
mile  cost  a  little  higher  than  if  all  the  work  as  it  stands  had 
been  done  at  once. 

In  heavier  wooden  pole  construction,  a  typical  example  is  a 
50,000-volt  to  60,000-volt  line  of  7-in.  top,  35-ft.  cedars  built  in  the 
eastern  part  of  the  Middle  West;  this  line  is  built  with  a  standard 

253 


254          TRANSMISSION  LINE  CONSTRUCTION 

pole  spacing  of  125  ft.  and  poles  are  arranged  with  two  arms,  a 
5-in.  X  7-in.  X  5-ft.  arm  at  the  top  with  a  5-in.  x7-in.  X8-ft.  arm 
5  ft.  below;  the  5-ft.  arm  carries  a  1/4-in.  B.  W.  G.  solid  galva- 
nized ground  wire  and  one  of  the  No.  2  copper  strand  conductors; 
the  lower  arm  carries  the  other  two  phase  wires;  the  ground  wire 
is  carried  on  a  pony  insulator  at  the  end  of  a  tall  wooden  pin  and 
the  line  insulators  are  standard  three-part  11  in.  supported  on 
treated  wooden  pins.  This  line  was  built  prior  to  the  drop  in 
the  price  of  copper  in  1907  and  the  mile  cost  complete,  with  a 
total  length  of  line  of  about  40  miles,  is  given  as  about  $2169. 

A  60,000-volt  line  using  the  same  cross-arm  arrangement  as  in 
the  case  just  described,  on  9-in.  top,  40-ft.  cypress  poles,  was 
built  in  the  north  central  part  of  the  Middle  West  in  1908-09; 
these  poles  were  set  in  125-ft.  spans  and  carried  a  single  cir- 
cuit of  copper  strand  made  up  of  seven  No.  10  B.  &  S.,  a  No.  5 
hard-drawn  copper  ground  wire  and  a  No.  10  B.  &  S.  copper 
telephone  circuit.  The  cross-arms  were  long-leaf  yellow  pine  of 
the  dimensions  given  in  the  preceding  description,  and  were 
through-bolted  with  3/4-in.  plain  bolts,  and  braced  with  2-in.  X 
5/16-in.  galvanized  braces.  The  line  pins  were  of  the  separable 
type  with  the  thimble  cemented  in  the  insulator  at  the  factory; 
the  ground  pins  were  a  standard  wood-based  steel  bolt  pin  with 
extra  shank  and  carried  a  porcelain  pony  insulator  to  which  the 
ground  wire  was  tied  in;  ground  taps  were  made  at  every  fifth 
pole  with  No.  8  B.  &  S.  soft-drawn  copper  soldered  to  a  7-ft. 
length  of  3/4-in.  galvanized  pipe  which  was  driven  full  length 
into  the  ground  at  the  butt  of  the  pole;  galvanized  malleable 
iron  brackets  lagged  to  the  pole,  carried  the  3-in.  telephone 
insulators.  This  line  was  built  through  a  well-settled  country 
with  a  sandy  loam  soil,  was  about  25  miles  long,  and  used  the 
public  highways  for  about  one-third  of  its  length;  the  cost  per 
mile  complete,  not  including  general  expense  or  general  super- 
vision, averaged  $2041. 

In  the  Electrical  World  for  Jan.  13.,  1912,  the  cost  of  the  Cal- 
gary, Can.  55,000-volt  line  is  given  as  about  $2000  per  mile. 
This  line  is  about  50  miles  long  and  is  built  with  40-ft.  cedars 
spaced  thirty-five  to  the  mile,  or  about  150  ft.  apart;  at  the  top 
of  the  pole  is  carried  a  1/4-in.  seven-strand  galvanized  steel 
ground  wire,  with  a  single  pin  bracket-arm  extending  out  from 
the  pole  about  3  1/2  ft.  down  from  the  top  supporting  one  of 
the  phase  wires,  and  a  regular  two-pin  cross-arm  below  this 


COST  DATA  255 

at  the  ends  of  which  are  the  other  two  phase  wires;  7  ft.  below 
the  main  conductors  is  a  two-pin  telephone  arm,  carrying  the 
private  telephone  line.  The  line  conductors  are  No.  0  alu- 
minum carried  on  standard  porcelain  insulators;  the  overhead 
ground  wire  has  taps  to  ground  at  every  third  pole;  every 
tenth  pole  is  double-armed  and  double-pinned,  and  is  pro- 
vided with  head  and  side  guys. 

In  steel  tower  construction  a  typical  single-circuit  line  with 
ground  wire  was  that  built  in  the  north  central  part  of  the  Middle 
West  in  1908;  this  line  was  constructed  with  50-ft.,  2300-lb. 
galvanized  towers  set  eleven  to  the  mile  or  with  480-ft.  spans, 
through  a  sparsely  settled  country  for  more  than  a  third  of  the 
distance  and  was  not  very  accessible,  requiring  long  hauls  in 
distributing  the  material,  and  necessitating  the  establishment 
of  camps  to  accommodate  the  construction  crew  for  most  of  the 
work.  The  total  length  of  line  was  about  46  miles  and  included 
a  river  crossing  on  special  structures,  where  the  working  condi- 
tions were  very  unfavorable,  and  about  5  miles  of  extremely 
bad  bottom  ground;  in  general  the  digging  was  fair  as  the  soil 
was  a  sandy  loam. 

The  towers  were  of  standard  four-post  design  bolted  to  anchor 
stubs,  set  in  the  ground  without  any  concrete;  the  insulators 
were  a  standard  four-part  66,000-volt  design,  supported  on 
separable  type  pins  with  galvanized  fittings;  the  conductors 
were  of  seven-strand  copper,  made  up  of  No.  10  B.  &  S.  wire, 
giving  a  section  between  No.  1  and  No.  2  B.  &  S.,  and  the  ground 
wire  was  the  same  as  the  line  conductors;  this  latter  was  tied 
in  on  the  top  casting  in  the  same  way  as  the  line  wires  to  the  in- 
sulators; at  transpositions,  railroad  crossings,  etc.,  and  at  certain 
intervals  along  the  line,  Clark  clamps  were  used  in  place  of  the 
regular  wire  tie.  A  telephone  line  of  No.  5  hard-drawn  copper 
was  carried  on  the  towers  about  7  ft.  below  the  lowest  high-ten- 
sion conductor,  being  supported  on  a  3-in.  porcelain  insulator 
cemented  to  malleable-iron  galvanized  pins. 

The  right-of-way  for  this  line  was  secured  under  easement, 
and  the  construction  work  was  carried  on  from  late  summer  to 
the  end  of  that  year;  the  cost  of  the  work  complete,  but  not  in- 
cluding general  expense,  general  supervision,  or  interest  during 
construction,  averaged  $2928  per  mile. 

Another  steel  tower  line  of  about  the  same  voltage,  length 
and  capacity  was  built  in  the  northeastern  part  of  the  Middle 


256  TRANSMISSION  LINE  CONSTRUCTION 

West  at  a  cost  of  $2008  per  mile  average,  no  information  being 
given  as  to  whether  right-of-way  and  engineering  were  included; 
it  is  stated  however  that  no  linemen  whatever  were  used  in  the 
work. 

In  this  work  the  standard  towers  were  a  three-post  design, 
'40  ft.  high  set  ten  to  the  mile  or  with  a  span  length  of  528  ft.; 
these  towers  carry  three  No.  2  copper  strand  conductors,  and  a 
telephone  circuit,  but  no  ground  wire  and  are  designed  for  a 
total  tower  load  of  4000  Ib.  They  weigh  only  1600  lb.,  being 
much  lighter  than  would  be  used  in  the  East  for  that  size  of 
conductors  and  span,  judging  from  description  of  line  work  in 
that  section  of  the  country  as  given  in  the  technical  journals. 
The  insulators  were  a  standard  four-part,  14-in.,  60,000-volt 
design;  the  conductors  are  arranged  in  an  equilateral  triangle 
with  6-ft.  spacing. 

This  line  was  built  by  the  same  company  at  about  the  same 
time  and  under  about  the  same  conditions  as  the  wooden  pole 
line  previously  described  and  notecl  as  costing  $2169  per  mile,  so 
that  for  the  same  voltage  and  line  conductors,  and,  as  it  happens, 
based  upon  equal  lengths  of  line,  the  steel  tower  construction 
was  erected  at  a  first  cost  actually  lower  than  that  of  the  wooden 
pole  work.  As  previously  noted  no  linemen  were  employed  in 
the  steel  lower  construction,  even  the  stringing  of  the  wire  being 
carried  on  with  common  labor,  and  this  feature  is  cited  as  having 
made  possible  the  low  cost  of  the  work.  As  noted  in  Chapter 
VI,  the  possibility  of  using  unskilled  labor  for  most  portions  of 
steel  tower  construction  should  really  make  for  a  general  lower 
cost  than  now  obtains. 

Another  tower  line,  that  of  the  Amherst  Power  Company 
built  in  1910,  is  described  in  the  Electrical  World  for  Sept.  9, 
1911,  and  cost  data  for  various  parts  of  the  work  and  the  total, 
are  given.  This  line  is  constructed  with  45-ft.  four-post  towers 
as  standard  with  a  regular  span  length  of  500  ft. ;  the  structures 
are  of  the  double  "  A'7  or  the  so-called  Buckingham  type  with 
3-in.  X  3-in.  X  3/16-in.  corner  posts,  2-in.  X  2-in.  X  1/8-in.  girts 
and  diagonal  members  of  1  I/ 2-in.  Xl  1 /2-in.  X  1/8-in.  in  the 
bottom  panels,  with  I/ 2-in.  round  rods  the  rest  of  the  way.  The 
insulators  are  a  standard  four-part,  66,000-volt  design  14  7/8  in. 
in  height  and  are  supported  on  extra  heavy  2-in.  pipe  pins;  the 
line  wire  is  seven-strand  No  2  copper,  tied  in  with  a  double  loop 
tie  of  No  4  B.  &  S.  wire  served  out  around  the  conductor  on  each 


COST  DATA  257 

side  of  the  head;  a  7/16-in.  galvanized  steel  ground  cable  is 
carried  at  the  top  of  the4ower  and  a  telephone  circuit  of  1/4-in. 
steel  wire  is  supported  10  ft.  below  the  line  conductors.  Towers 
were  set  in  earth  or  concrete  according  to  the  nature  of  the  soil 
encountered. 

A  1200-ft.  river  span  is  carried  on  two  special  structures  giving 
the  conductors  a  clearance  to  ground  of  60  ft. ;  the  line  conductors 
here  are  a  1/2-in.  Siemens-Martin  cable  dead-ended  to  four- 
standard  insulators  at  each  tower  arranged  in  series  and  provided 
with  cast-iron  caps  to  which  is  bolted  a  4-in.  X  1/2-in.  steel  flat. 

The  total  length  of  this  line  is  only  8.5  miles,  so  that  the  cost 
of  the  river  span  and  some  concrete  protection  given  the  towers 
near  the  river,  affect  the  average  mile  cost  more  than  they  would 
in  the  case  of  a  longer  line.  The  cost  per  mile  for  labor  on  this 
line  is  given  at  $772,  not  including  contractor's  profit,  and  the 
material  cost  is  given  at  $2140,  or  a  total  of  $2912  for  labor  and 
material. 

These  figures  are  merely  for  labor  and  material  as  noted  and 
do  not  include  engineering,  right-of-way  and  contractor's  profit, 
which  the  figures  previously  given  have,  or  the  equivalents. 

The  cost  figures  for  labor  alone  on  a  double-circuit  line  built 
in  the  West  will  be  interesting;  the  standard  tower  for  this  line 
weighed  about  4400  Ib.  and  was  a  standard  four-post  design, 
arranged  to  carry  two  ground  wires,  two  three-phase  45,000-volt 
circuits  of  No.  00  copper  on  suspension  insulators,  and  a  telephone 
circuit;  one  ground  wire  and  three  conductors  were  arranged 
vertically  on  each  side  of  the  tower  head,  with  a  standard  height 
to  ground  of  45  ft.  All  of  these  towers  were  set  in  concrete  and 
the  soil  was  stony  for  about  half  the  distance  and  sandy  the 
rest  of  the  way;  the  work  was  done  by  contract  and  the  total 
length  of  line  was  only  4.2  miles,  with  a  span  length  of  528  ft., 
so  that  the  total  number  of  towers  was  forty-two. 

The  total  labor  cost  per  mile,  not  including  any  engineering 
work,  was  $1009;  the  men  were  quartered  in  a  camp  which  was 
practically  self-supporting,  and  the  contractor  was  paid  the 
following  scale  of  wages  for  the  labor  he  furnished: 

Common  labor  and  groundmen 28    cents  per  hour. 

Linemen 45    cents  per  hour. 

Foreman 50    cents  per  hour. 

Teamsters  with  team  and  wagon 56£  cents  per  hour. 

A  66,000-volt  double-circuit  tower  line  recently  built  in  the 

17 


258  TRANSMISSION  LINE  CONSTRUCTION 

northern  part  of  the  Middle  West,  with  a  length  of  20  miles  to 
25  miles,  is  a  good  example  of  suspension  insulator  construction. 
The  towers  are  standard  four-post  galvanized  angle  structures 
40  ft.  in  height  and  weigh  about  2650  lb.;  they  are  designed  to 
carry  one  No:  2  B.  &  S.  copper-clad  ground  wire,  two  three- 
phase  circuits  of  No.  0  hard-drawn  copper  with  hemp  center, 
and  a  telephone  circuit  of  No.  12  copper-clad  wirein528-ft.  spans; 
the  insulators  are  a  standard  design  of  the  suspension  type,  and 
three  units  are  used  on  straight  line  work.  The  towers  are  set 
in  concrete  throughout. 

An  expensive  river  crossing,  requiring  two  180-ft.  towers, 
was  necessary  in  this  work;  these  two  towers  alone  in  place  cost 
about  $10,000,  the  foundation  cost  being  about  $1,500;  naturally 
with  the  total  length  of  line  only  20  miles  to  25  miles,  the  high 
cost  of  this  river  crossing  brings  the  average  mile  cost  up  appre- 
ciably; the  right-of-way  for  this  line  cost  $26.50  per  tower  and 
the  copper  was  bought  on  a  16-cent  base. 

The  cost  of  the  construction  complete,  not  including  the 
special  work  at  the  river  crossing,  averaged  $4340  per  mile, 
and  $4807  per  mile,  including  everything. 

Total  figures  on  the  cost  per  mile  of  the  40,000-volt  combination 
tower  and  steel-pole  line  of  the  United  States  Reclamation 
Service  in  Arizona  will  be  interesting;  this  is  the  original  double- 
circuit  line  about  65  miles  long,  built  from  the  Roosevelt  Dam 
into  Phoenix,  Arizona,  with  a  total  of  610  towers  and  276 
tripartite  steel  poles.  The  towers  are  four-post,  angle-iron 
braced,  galvanized-steel  structures  30-ft.  in  height,  of  quite  light 
design,  single-braced  in  the  regular  type,  with  angle  and  special 
towers  double-braced.  The  structures  are  arranged  without  a 
ground  wire  and  carry  four  conductors  in  a  horizontal  plane  at 
the  top  of  the  tower  on  a  channel-iron  arm,  and  the  other  two 
below  on  a  shorter  arm,  the  conductors  being  arranged  in  inverted 
deltas  with  4-ft.  spacing;  the  tower  spacing  varies  from  360  ft.  to 
400  ft.  The  steel  poles  are  those  described  in  Chapter  V,  varying 
in  overall  length  from  40  ft.  to  50  ft.  with  three  weights  of  poles 
in  each  length;  they  are  set  in  concrete  for  one-tenth  of  their 
length  and  the  conductors  are  arranged  as  on  the  towers  except- 
ing that  the  short  arm  is  at  the  top  in  this  case;  the  spans  in 
the  pole  work  vary  from  300  ft.  to  400  ft. 

Outside  of  the  supports,  the  details  of  the  construction  are 
the  same  for  both  the  tower  and  the  pole  work;  the  insulators 


COST  DATA  259 

are  a  standard  three-part  design,  shipped  knocked  down  and 
assembled  in  the  field;  the  line  conductors  are  six-strand  copper 
with  hemp  center,  equivalent  to  No.  1  B.  &  S.  and  are  tied  in 
with  a  double  loop  and  clamp  tie. 

This  line  passes  through  some  very  rough  country  and  the 
labor  was  Indian,  to  a  great  extent;  the  cost  per  mile  complete 
averaged  $4400. 

In  flexible  tower  line  construction,  the  writer  has  been  unable 
to  secure  any  total-cost-per-mile  figures  but  through  the  courtesy 
of  the  Archbold-Brady  Company.,  obtained  data  as  to  the 
cost  of  structures  of  this  type  erected  complete,  as  noted  below. 

The  first  case  is  a  line  in  New  York  State  with  the  double- 
circuit  tower  shown  in  Fig.  34,  6;  this  tower  is  36  ft.  in  height 
from  the  ground  to  the  lowest  conductor  (ultimate),  and  is 
designed  to  carry  one  3/8-in.  ground  wire,  two  three-phase 
33,000-volt  circuits  of  No.  00  copper  strand,  and  two  1/4-in. 
steel  telephone  wires  in  400-ft.  spans;  at  the  present  time  only 
four  of  the  six  line  wires  have  been  strung.  The  cross-arms 
are  malleable  iron.  This  line  was  constructed  through  a  rather 
rough  country  with  a  fair  number  of  angles  and  quite  a  bit  of 
rock  work,  with  several  swampy  stretches;  the  stubs  for  the 
A-frames  and  the  anchor  towers  were  set  in  earth,  while  heavy 
corner,  and  dead-end  towers  were  set  in  concrete.  The  cost  of 
this  line,  exclusive  of  right-of-way,  pins,  insulators  and  wire, 
but  including  the  labor  of  stringing  wire,  is  given  as  about  $1600 
per  mile. 

A  60,000-volt  line  in  New  Hampshire,  20  miles  long,  employed 
the  structure  shown  in  Fig.  34,  c;  this  tower  is  also  36  ft.  in  height 
from  the  ground  to  the  lowes-t  conductor,  with  a  6-ft.  vertical 
spacing  between  conductors,  and  is  designed  to  carry  a  3/8-in. 
steel  ground  wire  and  two  three-phase  circuits  of  No.  00  copper, 
with  only  one  circuit  installed  at  the  present  time.  About  one- 
third  the  length  of  this  line  was  through  extremely  rough  country 
and  required  a  large  number  of  anchor  and  angle  towers;  the 
remainder  of  the  construction  was  through  average  country  with 
quite  long  tangents;  four  railroad  crossings  were  made  which  added 
considerably  to  the  cost  of  the  work;  the  anchor  towers  are  spaced 
approximately  1  mile  apart  and  occasionally  in  between,  the 
A-frames  were  head-guyed.  The  cost  of  this  work,  not  including 
right-of-way,  pins,  insulators,  and  wire,  averaged  about  $1800 
per  mile. 


260  TRANSMISSION  LINE  CONSTRUCTION 

In  single-circuit  construction,  with  this  class  of  structure  and 
suspension-type  insulators,  several  60,000-volt  lines  have  been 
recently  built;  the  tower  used  was  32  ft.  in  height  from  the  ground 
to  the  lowest  conductor,  with  a  width  at  the  ground  of  6  ft.; 
the  main  members  were  a  9.75  Ib.  7-in.  channel,  braced  with 
2  1/2-in.  X2  1/2-in.  Xl/4-in.  girts  and  5/8-in.  rod  diagonals, 
and  the  structure  was  designed  to  carry  a  ground  wire  and  a 
three-phase  circuit  of  No.  1  or  No.  2  copper  in  400-ft.  to  440-ft. 
spans,  the  insulators  being  swung,  from  angle-iron  bracket-arms. 
With  the  smaller  wire  the  structures  may  be  guyed  and  anchor 
towers  used  only  at  the  ends  of  the  line,  but  with  four-post 
structures  at  heavy  angles.  Lines  recently  constructed  as 
described  have  shown  an  approximate  cost  of  from  $850  to  $900 
per  mile,  the  figures  including  the  structures  set,  but  not  right- 
of-way,  insulators,  wire,  or  in  this  case,  the  stringing  of  the  wire. 

Cost  data  on  steel  pole  construction  are  not  abundant,  what 
little  are  available  being  confined  to  work  where  a  patented  pole 
has  been  used. 

The  first  case  is  a  light  13,200-volt  line  built  in  Iowa  in  1911; 
this  line  is  about  15  miles  long,  follows  the  public  highways,  and 
consists  of  36-ft.  steel  poles  set  in  concrete  with  an  average 
setting  of  eighteen  to  the  mile;  the  poles  carry  a  three-phase 
circuit  of  No.  6  B.  &  S.  hard-drawn  copper,  with  no  ground 
wire;  the  conductors  are  arranged  in  the  form  of  an  equilateral 
triangle  with  a  spacing  of  5  ft.;  the  pins  are  of  steel  with  lead 
tops,  the  ridge  pin  being  screwed  into  the  top  casting  of  the  pole 
and  the  other  two  carried  on  a  64-in.  angle-iron  cross-arm,  with 
a  light  angle-iron  brace;  six  60-ft.  and  four  50-ft.  poles  were  used 
at  points  along  the  line.  The  insulators  used  on  the  steel  poles 
were  a  standard  23,000-volt  type. 

The  company  which  constructed  and  is  operating  this  line, 
gives  the  average  cost  per  mile  as  $610.56;  the  wooden  pole  line 
of  which  the  above  line  is  a  continuation,  and  which  has  been 
described  at  the  beginning  of  this  chapter  cost  $625.82.  The 
manager  of  the  company  states  that  they  secured  exceptional 
prices  on  all  their  material  for  the  steel  line  and  really  believes 
that  under  similar  conditions,  the  first  cost  of  the  steel  line 
might  be  a  little  higher  than  that  of  the  wooden  pole  construction 
for  13,200  volts. 

Another  line  built  in  Colorado  with  this  same  patented  pole, 
used  a  35-ft.  length  as  standard,  with  other  sizes,  as  necessary, 


COST  DATA  261 

from  25  ft.  to  45  ft.  long;  these  poles  were  arranged  with  a  5-ft. 
conductor  spacing  in  the  same  manner  as  the  design  for  the  line 
just  described,  and  the  poles  were  spaced  from  sixteen  to  eight- 
teen  to  the  mile,  set  in  concrete;  the  line  voltage  is  11,000  volts 
and  the  conductors  are  No.  3  B.  &  S.  copper. 

The  cost  of  this  line  complete  is  given  as  a  little  over  $1000 
per  mile,  with  a  total  length  of  line  of  about  15  miles.  It  may 
be  noted  that  one-fifth  of  the  distance  was  solid  rock  setting  and 
the  rest  of  the  way  the  soil  was  a  coarse  gravel;  the  work  was 
done  by  contract. 

The  cost  of  concrete  pole  lines  is  somewhat  problematical  for 
work  carried  on  under  the  average  conditions  that  will  obtain  in 
transmission  line  construction,  in  that  most  of  the  work  done  up 
to  the  present  time  has  been  carried  on  under  conditions  es- 
pecially favoring  the  handling  and  erection  of  that  kind  of 
poles. 

In  and  around  Oklahoma  City,  Oklahoma,  the  cost  is  given 
by  J.  M.  Brown,  superintendent  of  lines  for  the  Oklahoma 
Gas  &  Electric  Company,  as  about  50  per  cent,  greater  than  that 
of  wood  of  corresponding  length  and  size;  it  may  be  noted  that 
the  above  company  has  about  40  miles  of  this  type  of  con- 
struction in  service,  but  that  their  experience  is  confined  mostly 
to  city  distribution  work.  Other  sources  of  information  give  as 
an  estimate  that  concrete  pole  lines  will  cost  about  25  per  cent, 
less  than  that  of  steel  pole  construction  of  equivalent  safe 
strength. 


CHAPTER  XIII 
ORGANIZATION  AND  TOOLS 

The  actual  planning  and  systematic  preparation  for  the 
carrying  out  of  a  transmission  line  project  deserves  more  atten- 
tion than  has  usually  been  accorded  it  in  the  past.  When  a 
hydro-electric  development  is  to  be  put  under  way,  the  various 
steps  and  operations,  with  the  most  economical  methods  of 
carrying  them  on,  are  carefully  studied  and  decided  upon,  and 
estimates  are  made  of  the  time  required  in  the  form  of  a  pro- 
spective log  of  the  work,  the  details  of  the  work  and  progress 
on  the  coffer-dams,  excavation,  dam,  core-walls,  power-house, 
etc.,  etc.,  being  carefully  worked  out,  but  the  transmission  line 
is  usually  lumped  off,  to  be  gone  into  more  thoroughly  when 
the  work  is  to  be  started. 

The  reason  for  leaving  the  construction  of  the  line  to  the 
last  is  apparent  where  the  work  of  development  is  to  extend 
over  a  term  of  two  or  three  years,  as  it  would  be  poor  business 
policy  to  pay  interest  on  dormant  investment,  but  on  the  other 
hand,  the  practice  that  often  obtains  of  neglecting  the  line  until 
it  is  too  late  to  carry  on  the  work  in  an  economical  manner, 
cannot  be  too  strongly  condemned.  With  initial  line  work 
often  amounting  to  from  15  per  cent,  to  25  per  cent,  of  the 
total  cost  of  the  development,  it  should  merit  as  close  atten- 
tion as  other  features  of  the  work. 

In  opening  up  a  job,  the  keystone  of  the  organization  is  of 
course  the  general  foreman;  he  should  be  a  man  of  not  only 
constructive  ability  but  executive  as  well,  and  remembering 
the  sad  fact  that  very  many  high-class  line  foremen  are  addicted 
to  the  use  of  alcoholic  stimulants  to  excess,  it  is  well  to  add 
that  he  should  be  of  temperate  habits;  a  " booze-fighting" 
foreman  usually  means  a  " booze-fighting"  crew  and  a  break 
in  the  work  just  as  often  as  pay  day  comes  around.  A  man 

262 


ORGANIZATION  AND  TOOLS 


263 


who  can  use  his  head  and  cope  with  unforeseen  difficulties  and 
who  can  get  an  efficient  day's  work  out  of  his  crew,  is  a  valuable 
man  in  any  kind  of  construction  work  and  especially  so  in  line 
work;  the  measure  of  a  foreman's  efficiency  is  not  necessarily 
determined  either,  by  his  ability  to  drive  his  men;  a  crew  that 
is  worked  along  smoothly  and  easily  will  usually  show  a  better 
day's  progress  than  one  that  is  being  constantly  pushed;  also 


LA    CROSSE    WATER     POWER    COMPANY 


FOREMAN'S    DAILY    REPORT 


DAY    OF    WEEK 

19 


(Note.      Foremen  should  divide  the  time  on  the  various  classes  of  work  done.) 


RATE      AMOUNT 


APPROVED 


Report  on  other  side  kind  and  amount  of  work  done. 

FIG.  181. — Form  for  reporting  on  line  work. 


264          TRANSMISSION  LINE  CONSTRUCTION 

if  the  foreman  be  gentlemanly,  diplomatic,  and  a  good  "mixer/' 
he  can  do  the  company  service  of  inestimable  value  in  estab- 
lishing a  good  will  and  friendly  feeling  toward  it  among  the 
people  residing  in  the  territory  traversed.  To  the  general 
foreman,  within  limits,  should  be  left  the  selection-  of  the  crew 
foremen. 

With  the  general  foreman,  the  engineer  can  make  plans  for 
the  handling  of  the  work,  the  methods  to  be  employed  for  the 
digging,  raising,  setting,  etc.,  the  assembling  of  the  crews,  the 
intervals  between  the  beginning  of  the  various  steps,  the  probable 
time  required  for  the  different  operations,  etc.,  all  of  which 
should  be  definitely  decided  upon  to  bring  the  work  to  com- 
pletion within  a  certain  specified  time. 

The  matter  of  reporting  the  time  of  the  men  should  also  be 
given  study;  the  system  that  is  much  used  is  to  have  the  fore- 
man of  each  gang  keep  the  time  of  his  men  in  a  standard  time 
book,  and  then  in  addition  to  that,  make  out  for  each  day  a 
report  on  a  form  such  as  shown  in  Fig.  181,  the  report  to  be 
approved  by  the  general  foreman  and  mailed  to  the  office.  A 
better  plan  is  to  have  one  timekeeper  or  more  as  may  be  re- 
quired, to  take  care  of  this  work  rather  than  to  leave  it  to 
the  foremen,  though  the  latter  will,  of  course,  make  out  the  daily 
reports. 

As  will  be  noted,  this  report  is  a  distribution  and  progress 
report,  that  is,  the  time  of  the  men  is  distributed  in  the  vertical 
columns  so  as  to  be  charged  to  the  various  operations  in  which 
they  may  have  been  engaged  during  that  working  day;  letters, 
or  numbers,  are  usually  employed  to  designate  the  different 
operations,  as,  for  instance,  "A"  may  be  "  clearing  right-of-way/' 
"B,"  "  distributing  poles/'  etc.,  so  that  the  labor  cost  of  the 
various  parts  of  the  work  can  be  segregated  easily  and  without 
involving  the  foremen  in  too  much  "red  tape." 

On  the  reverse  side  of  the  sheet  is  a  log  of  the  day's  progress 
of  the  crew  from  which  the  general  foreman  and  the  engineer 
can  determine  the  headway  made  in  the  work,  and  keep  track 
of  the  relative  efficiencies  of  the  different  crews. 

Often  graphical  progress  charts  are  used  in  addition  to  the 
daily  reports  made  on  the  reverse  side  of  the  distribution  sheet 
described  or  sometimes  are  incorporated  with  it,  the  latter 
being  preferable;  these  usually  take  the  form  shown  in  Fig. 
182,  below. 


ORGANIZATION  AND  TOOLS  265 

This  report  made  out  daily  by  the  crew  foreman  and  mailed 
in  with  the  time  reports,  allows  a  total  chart  to  be  plotted  in 
the  office  so  that  the  engineer  is  not  only  well  in  touch  with 
the  daily  progress  of  the  different  crews,  but  knows  the  actual 
condition  of  the  work  at  the  end  of  each  day,  for  the  complete 
job.  The  weather  report  noted  on  the  progress  chart  gives 
the  conditions  under  which  the  day 's  work  has  been  prosecuted 
and  helps  in  determining  the  causes  for  a  variation  from  the 
rate  at  which  any  crew  has  been  generally  working. 


WEATHER:- 

Rain  -  Snow  Day  of  the  week 

o 
»•••••  %|»4|»41»4    feL>     «* 


,1 


KEY 

©       Material  distributed 

©       Hole  duq  or  anchors  set 

•       Pole  or  tower  erected 

•I       Cross  arms  on 

•I       Insulators  on 
"•T      Wire  strung 
IS      Wire  pulled  up  and  tied  in 

FIG.  182. — Progress  chart. 

A  close  check  on  the  handling  of  all  material  is  necessary,  and 
it  is  a  good  policy,  where  the  magnitude  of  the  work  warrants 
it,  to  employ  a  material  man  to  take  charge  of  all  incoming  ship- 
ments, checking  them  over  and  reporting  shortages,  breakages, 
etc.,  to  the  general  foreman  to  whom  he  should  be  directly 
responsible,  and  also  to  issue  to  the  various  crew  foremen,  mate- 
rial as  needed,  for  which  receipts  should  be  taken;  where  the  work 
is  carried  on  at  several  diverse  points  simultaneously,  he  will  of 
course  have  such  assistants  as  may  be  required.  At  each  place 
where  a  material  man  is  stationed  he  should  keep  a  stock  book, 
preferably  loose  leaf,  with  the  sheets  arranged  as  shown  in  Fig. 
183,  a  new  book  being  made  up  for  each  month  and  the  sheets 
for  the  previous  period  filed  away.  This  method  of  keeping 


266 


TRANSMISSION  LINE  CONSTRUCTION 


MATERIAL    RECORD 


COM  MODITY 


FOR     MONTH    OF 19 


INCOMING     MATERIAL 


DATE 

FROM   WHOM    RECEIVED 

QUANTITY 

REMARKS 

Brought  Fwd.  from  last  month 

Total 

OUTGOING     MATERIAL 


DATE 

DESTINATION 

QUANTITY 

SIGNED  FOR  BY 

Total 

Balance  on  hand  at  end  of  month 

FIG.  183. 


track  of  the  material  gives  a  good  record  of  incoming  and  out- 
going material  and  at  the  same  time  shows  clearly  what  is  at  hand 
at  any  time,  being  in  fact  a  perpetual  inventory. 


ORGANIZATION  AND  TOOLS  267 

The  problem  of  keeping  tab  on  company  tools  is  a  bothersome 
one;  linemen  proper,  furnish  their  "hooks/7  belt  and  safety, 
pliers  and  connectors  as  a  rule,  but  groundmen  do  not  carry  any 
tools  at  all;  so,  in  steel  tower  work  especially,  the  company  must 
furnish  practically  everything  in  the  way  of  tools  on  the  job. 
Wrenches,  hammers,  etc.,  are  highly  prized  as  " souvenirs" 
by  the  average  construction  man  and  few  jobs  are  completed  with- 
out having  a  considerable  number  of  tools  charged  up  as  "lost," 
regardless  of  all  efforts  to  the  contrary. 

The  system  that  for  ordinary  line  work,  where  each  crew  has  a 
team  and  teamster,  has  worked  out  very  well  for- the  writer,  is 
to  charge  each  foreman  with  a  tool  box  equipped  with  all  the 
necessary  hand  tools,  and  with  a  complement  of  shovels,  spoons, 
pikes,  blocks  and  tackle,  etc.,  etc.,  depending  upon  the  work 
being  done,  and  hold  him  personally  responsible  for  the  same; 
the  teamster,  however,  acts  as  the  actual  toolkeeper  and  issues 
to  the  men  the  tools  they  may  require  upon  arriving  at  the  job, 
checking  them  in  and  locking  the  chest  at  the  close  of  the  day's 
work;  the  foreman  will,  of  course,  hold  him  responsible  for  tools 
that  are  issued  and  not  turned  in.  With  all  tools  thus  checked 
in  each  evening,  the  loss  of  tools  can  be  reduced  to  a  minimum. 

A  tool  chest  properly  fitted  with  trays  and  with  the  place  for 
each  tool  outlined  or  silhoutted,  will  very  materially  aid  the  tool- 
keeper  in  keeping  tab  on  his  outfit  of  hand  tools;  in  connection 
with  the  foregoing  it  may  be  well  to  note  that  a  saw-filing  outfit 
and  a  small  portable  grindstone  are  a  very  profitable  part  of  the 
tool  equipment,  not  only  ensuring  suitable  facilities  for  the  main- 
tenance of  the  edged  tools,  etc.,  but  providing  a  means  of  employ- 
ment for  the  straight-time  men  on  rainy  days. 

The  problem  of  housing  and  feeding  a  crew  in  the  field  is  one 
that  is  omnipresent,  and  resorting  to  camps  by  no  means  absolves 
one  from  the  trials  and  tribulations  incident  to  other  means  of 
providing  sustenance.  Where  there  are  a  number  of  small 
villages  located  near  the  line,  the  crew  can  be  quartered  in  the 
local  hotels — the  "s"  is  usually  missing — where  the  commercial 
traveler  pays  tribute  at  the  rate  of  $2  a  day,  the  town  folks  at 
about  $4  per  week,  and  the  company  whatever  the  "traffic  will 
bear,"  usually  about  $1  a  day  in  the  Middle  West.  When  the 
crew  is  staying  at  a  hotel  at  some  little  distance  from  the  line,  the 
noon  meal  is  either  packed  up  in  the  morning  and  carried  along, 
or  a  hot  lunch  is  sent  out  to  the  boys  at  noontime;  the  latter 


268  TRANSMISSION  LINE  CONSTRUCTION 

method  is  a  much  better  policy  as  a  man  can  do  far  better  work 
on  a  warm  meal  than  he  can  on  a  cold  lunch,  and  the  additional 
expense  of  providing  for  the  warm  meal  is  amply  compensated 
for  on  the  progress  chart. 

Again  quite  frequently  it  is  possible  to  send  one  of  the  men  out 
in  the  morning  and  arrange  for  dinner  for  the  crew  at  some  farm- 
house close  by,  where  the  "haus-frau"  is  not  averse  to  adding 
to  her  pin-money  in  this  way. 

Where  it  is  not  feasible  to  undertake  the  extra  distance  to  a 
village,  where  the  country  is  fairly  well  settled  it  is  often  possible 
to  quarter  the  men  among  the  nearby  farmers  entirely,  though  as 
a  rule  the  accommodations  at  a  farm-house  are  quite  limited  and 
the  crew  will  have  to  be  divided  up  among  a  half-dozen  different 
places;  with  the  men  scattered  in  this  way  it  is  harder  for  the 
foreman  to  keep  track  of  things  that  are  going  on  and  to  main- 
tain discipline.  This  method  of  providing  for  a  crew,  however, 
works  out  very  well  where  the  crew  is  not  so  large,  and  the  class 
of  farm-houses  is  such,  that  they  can  all  be  taken  care  of  at  two 
or  three  places. 

Where  the  crew  is  too  large  to  be  quartered  on  farms  and 
where  there  are  no  villages  close  in  to  the  line,  as  well  as  in  the 
case  of  a  line  passing  through  unsettled  country,  a  camp  must  be 
established  for  the  accommodation  of  the  men.  There  are  two 
ways  of  handling  the  camp  question,  either  the  company  itself 
can  operate  it,  or  the  privilege  can  be  turned  over  to  some 
"boarding  boss/'  who  contracts  to  furnish  meals  and  sleeping- 
quarters  for  a  certain  minimum  number  of  men  at  so  much  a 
day  or  week,  the  same  being  charged  against  each  man  on  the 
pay-roll  and  deducted  from  his  check;  this  guarantees  the  "  board- 
ing boss  "  against  loss  and  at  the  same  time  provides  the  company 
with  a  means  of  insuring  reasonably  good  service  to  its  employees. 

Where  the  company  itself  attempts  to  operate  the  camp,  it 
usually  finds  the  proposition  to  be  an  expensive  experience,  due 
to  the  fact  that  the  foreman  of  the  crew,  who  will  be  in  charge  of 
the  whole  as  a  rule,  has  generally  no  knowledge  of  the  economical 
carrying  on  of  this  part  of  the  work,  and  furthermore  has  no  time 
to  devote  to  it  during  the  day,  with  the  result  that  he  has  to 
depend  upon  the  camp  cook  for  the  handling  of  the  details, 
with  neither  knowledge  nor  opportunity  for  proper  checking. 
Also  in  the  matter  of  purchasing  and  getting  in  supplies,  the  com- 
pany is  handicapped  by  the  fact  that  it  always  costs  a  corporation 


ORGANIZATION  AND  TOOLS  269 

more  for  supplies  and  service  than  it  does  a  private  individual  in 
a  case  like  this,  for  the  reason  that  the  foreman  has  no  time,  and 
the  cook  usually  no  inclination,  to  investigate  weights,  qualities 
and  prices;  on  the  other  hand  the  "boarding  boss"  is  usually  a 
local  man  who  in  small  camps  personally  attends  to  most  of  the 
cooking,  does  all  his  own  purchasing,  has  his  own  "tote-wagon," 
and  who  has  no  other  duties  to  attend  to  save  those  of  keeping  up 
the  tent  homes  of  the  crew  and  providing  their  meals  on  schedule 
time,  so  that  he  is  in  a  position  to  observe  all  the  economies  pos- 
sible to  the  average  housewife.  Where  a  camp  contract  can  be 
made  with  a  reliable  and  capable  man,  the  same  should  certainly 
be  done,  as  the  company  will  be  spared  a  great  expense  and 
annoyance. 

For  a  camp  equipment  to  take  care  of  about  thirty  or  so  men, 
two  14-ft.  X20-ft.  wall  tents  pitched  end  to  end  will  make  a  good 
bunk  tent,  and  a  similarly  arranged  pair  of  the  same  size  will 
be  sufficient  for  a  cook  and  mess  tent;  the  bunks  in  the  sleeping 
tent  are  usually  straw-filled  ticks  laid  on  the  ground  with  a 
tarpaulin  or  a  loose  board  floor  underneath,  and  provided  with 
plenty  of  blankets  if  the  work  be  carried  on  in  cold  weather; 
when  required,  two  sheet-metal  stoves  will  provide  all  the  heat 
necessary  to  keep  the  tent  comfortable.  For  the  mess  tent  the 
table  will  usually  consist  of  a  top  of  light  inch-boards  cleated 
together  and  supported  on  light  horses,  while  the  seats  will  be 
long  wooden  benches;  for  the  cook  tent  the  necessary  comple- 
ment of  pots,  dishes,  and  pans,  with  a  sheet-metal  camp  cook 
stove,  will  have  to  be  provided. 

Where  the  conditions  are  such  as  to  require  a  camp,  it  is  the 
general  rule  for  a  commissary  to  operate  in  connection  with  it, 
where  the  men  can  procure  overalls,  socks,  handkerchiefs, 
tobacco,  etc. 

Where  the  work  is  carried  on  in  the  winter  time  and  teams 
must  be  quartered  in  camp^  some  sort  of  a  barn  tent  will  also 
have  to  be  provided. 

The  manner  in  which  the  services  of  teams  will  be  secured 
will  vary  with  the  character  of  the  country  passed  through  and 
the  season  of  the  year  during  which  the  work  is  prosecuted. 

In  a  well-settled  farming  community  it  will  be  almost  im- 
possible to  hire  teams  for  hauling  material  during  the  summer 
months  and  also  at  times  in  the  spring  and  fall,  but  during  the 
winter  period  any  number  will  be  available  and  generally  at 


270  TRANSMISSION  LINE  CONSTRUCTION 

from  $3.25  to  $3.75  a  day  in  the  Middle  West,  so  that  under  such 
conditions  it  is  most  economical  to  arrange  matters  so  that  the 
heavy  material  will  be  hauled  out  in  the  winter  time;  where 
sleighing  can  be  figured  on  the  advantages  of  hauling  out  poles 
and  towers  on  sleds  with  the  greater  loading  possible,  should 
also  be  taken  advantage  of. 

In  the  small  villages  along  the  line,  however,  it  is  usually  pos- 
sible to  secure  such  teams  as  will  be  needed,  and  in  carrying  on 
work  in  the  summer  months  these  will  have  to  be  depended 
upon;  in  isolated  regions  and  in  non-agricultural  districts  it 
often  happens  that  it  is  necessary  to  contract  for  the  hauling 
with  a  teaming  contractor  from  some  nearby  town,  either  on  a 
tonnage  or  a  per  diem  basis. 

Where  teams  are  required  steadily  to  attend  the  crews  in  the 
course  of  the  construction,  they  may  be  placed  on  a  day  basis 
and  the  teamsters  provide  their  own  maintenance  and  that  of 
their  team,  or  they  may  be  hired  at  so  much  a  month  with  all 
expenses  paid;  where  the  teams  are  from  the  locality  in  which 
the  work  is  going  on,  the  writer  has  found  it  to  be  more  satis- 
factory and  more  economical  to  secure  them  on  the  former 
basis,  as  the  stablemen  and  farmers  along  the  line  usually  have 
one  scale  of  prices  for  local  people  and  another  for  transients, 
with  often  an  extra  tax  on  corporations. 

In  the  prosecution  of  any  work  remote  from  quick  medical 
attendance,  a  contingency  that  should  be  provided  for  is  that  of 
accident.  The  forehian  of  each  crew  should  be  furnished  with  an 
emergency  chest,  equipped  with  bandages,  absorbent  cotton, 
antiseptics,  etc.  In  the  case  of  an  accident,  the  foreman  should  be 
instructed  to  summon  comp.etent  medical  attendance  at  once  if  at 
all  warranted  and  if  the  case  be  serious,  he  should  wire  the 
general  foreman  or  the  main  office;  in  the  event  of  any  accident, 
however  slight,  incurred  in  the  course  of  the  work,  the  foreman 
should  be  required  to  make  out  a  complete  report  of  the  same 
on  blanks  provided  for  that  purpose;  a  form  much  used  for  that 
purpose  is  given  below: 

This  form  is  adapted  to  general  construction  and  properly 
filled  out  will  give  a  complete  record  of  the  happening. 

Prompt  and  considerate  attention  to  personal  injury  cases 
should  be  the  policy  always;  and  it  has  been  the  experience  of 
most  large  companies  that  a  fair  and  square  deal  accorded  to 
injured  employees  will  in  most  cases  do  away  with  damage  suits. 


ORGANIZATION  AND  TOOLS  271 

REPORT  OF  ACCIDENT  TO  AN  EMPLOYEE 

Of 

Of  (Give  full  address) Street;    City State 

In  case  of  fatal  accident  or  serious  injury,  telephone  or  telegraph  at  once 
— giving  date  of  inquest  if  any. 

INJURED  PERSON'S  NAME  ?  ...  .About  how  old? .... 

Wages? Nationality? 

Address  in  full? Married  or  Single? 

Occupation? ....  How  long  employed? 

In  whose  employ  at  time  of  accident? 

Had  he  done  similar  work  prior  to  this  employment? 

DATE  OF  ACCIDENT? 191....  Hour M.    Was  light  good?... 

PLACE  WHERE  ACCIDENT  OCCURRED? 


Describe  the  place,  machinery,  tools,  1   

staging,   etc.,    connected  with   the   > 

accident.  )  

Was  it  sound  and  in  good  working  order? Who  can  prove  this? 

Nature  and  extent  of  INJURY? 

Taken  home  or  to  hospital? Attending  doctor's  name  and  address? 

(If  hospital,  which  one.) 
Period  of  disablement? Has  injured  resumed  work? 

Names  and  addresses  of  witnesses?  ... 


jrson  i 
ames  > 
it.  ) 


Give  statement  made  by  injured  person 

as   to   cause  of  accident,   and   names 

and  addresses  of  those  who  heard 

Name  and  address  of  foreman  in  charge  of  work? 

Where  was  he  at  time,  and  what  was  he  doing? 

Was  accident  due  to  want  of  ordinary  care  on  part  of  injured  person? 

Narrate  below  how  the  accident  happened,  its  causes,  etc.,  illustrating  if  possible,  by  a  rough  sketch. 


Notes  made  out  by whose  position  in  our  employ  is.. 

Date  of  Notice..  , 191. 


APPENDIX    A 

STANDARD  SPECIFICATIONS  FOB  WHITE  CEDAR  TELEGRAPH, 
TELEPHONE  AND   ELECTRIC  POLES 

Sizes,  5-in.,  25-ft.  and  upward.  Above  poles  must  be  cut 
from  live  growing  timber,  peeled  and  reasonably  well  propor- 
tioned for  their  length.  Tops  must  be  reasonably  sound,  and 
when  seasoned  must  measure  as  follows:  5-in.  poles,  15  in. 
circumference  at  top  end;  6-in.  poles,  18  1/2  in.  in  circum- 
ference at  top  end;  7-in.  poles,  22  in.  circumference  at  top  end. 
If  poles  are  green,  fresh  cut  or  water  soaked,  then  5-in.  poles 
must  be  5  in.  plump  in  diameter  at  top  end,  6-in.  poles  must  be 
19  1/2  in.  in  circumference,  and  7-in.  poles  22  3/4  in.  in  circum- 
ference at  top  end.  One  way  sweep  allowable  not  exceeding 
1  in.  for  every  5  ft.;  for  example,  in  a  25-ft.  pole,  sweep  not  to 
exceed  5  in. ;  and  in  a  40-f t.  pole,  8  in. ;  in  longer  lengths  1  in. 
additional  sweep  permissible  for  each  additional  5  ft.  in  length. 
Measurement  for  sweep  shall  be  taken  as  follows:  That  part  of 
the  pole  when  in  the  ground  (6  ft.)  not  being  taken  into  account 
in  arriving  at  sweep,  tightly  stretch  a  tape  line  on  the  side  of  the 
pole  where  the  sweep  is  greatest,  from  a  point  6  ft.  from  butt  to 
the  upper  surface  at  top,  and,  having  so  done,  measure  widest 
point  from  tape  to  surface  of  pole  and  if,  for  illustration,  upon  a 
25-ft.  pole  said  widest  point  does  not  exceed  5  in.  said  pole 
comes  within  the  meaning  of  these  specifications.  Butt  rot  in 
the  center  including  small  ring  rot  outside  of  the  center;  total 
rot  must  not  exceed  10  er  cent,  of  the  area  of  the  butt.  Butt 
rot  of  a  character  which  plainly  seriously  impairs  the  strength 
of  the  pole  above  ground  is  a  defect.  Wind  twist  is  not  a  defect 
unless  very  unsightly  and  exaggerated.  Rough  large  knots  if 
sound  and  trimmed  smooth  are  not  a  defect. 


272 


APPENDIX    B 

SPECIFICATIONS  FOR  STEEL  TOWERS  FOR  TRANSMISSION  LINE 

General. — Whenever  the  word  "  purchaser"  is  used  herein  it  is 
understood  to  refer  to  the  purchaser's  engineer  or  the  authorized 
assistant  of  said  engineer. 

Whenever  the  word  "contractor"  is  used  herein  it  is  under- 
stood to  refer  to  the  party  or  parties  to  whom  the  contract  for 
the  work,  or  any  part  or  parts  of  the  work,  may  be  awarded,  or  the 
authorized  agent  of  such  party  or  parties. 

Whenever  the  word  "work"  is  used  herein,  it  shall,  except 
where  by  the  context  another  meaning  is  clearly  intended, 
mean  the  whole  of  the  materials  and  labor  and  other  things 
required  to  be  done,  furnished  and  performed  by  the  contractor 
under  these  specifications. 

The  towers  covered  by  these  specifications  are  to  be  used  to 
support  the  insulators,  conductors,  and  ground  wire  for  an  elec- 
tric-power transmission  line. 

The  towers  shall  be  designed  to  support 
6  line  conductors, 

1  3/8-in.  seven-strand  steel  ground  wire, 

2  telephone  wires. 

The  arrangement  of  the  conductors,  ground  wire  and  tele- 
phone line  supports  and  pins  shall  be  in  accordance  with  drawing 
2134-S,  hereto  attached  and  a  part  of  these  specifications. 

Strength  of  Towers. — The  assembled  tower  shall  be  required 
to  stand  the  following  mechanical  load  tests  without  distorting 
appreciably  or  causing  any  member  to  exceed  its  elastic  limit. 

1.  At  conductor  pin  tops: 

1500  Ib.  in  any  direction  perpendicular  to  the  axis  of 
the  pin. 

2.  Ground  wire  support  at  clamp: 

1500  Ib.  applied  in  any  direction  perpendicular  to  the 
axis. 

3.  Tower  structure: 

6000  Ib.  applied  at  the  middle  cross-arm  in  any  direc- 
tion perpendicular  to  the  axis  of  the  tower, 
is  273 


274  TRANSMISSION  LINE  CONSTRUCTION 

The  base  of  each  tower  shall  be  14  ft.  square  and  the  legs 
provided  with  detachable  ground  stubs  6  ft.  long  supplied  with 
suitable  footing  plates  not  less  than  2  ft.  6  in.  in  length. 

The  standard  height  of  the  towers  shall  be  36  ft.  measured 
from  the  ground  stub  joint  to  the  lowest  conductor. 

Metal  steps  shall  be  provided  to  within  8  ft.  of  the  ground  so 
as  to  allow  of  safe  access  to  either  circuit  while  the  other  is 
alive. 

Insulator  pins  for  the  line  conductors  shall  be  of  the  separable 
type  in  general  accordance  with  the  dimensions  given  on  drawing 
2134-S,  and  shall  be  easily  detachable  from  the  cross-arm;  they 
shall  also  be  designed  to  permit  their  installation  on  the  cross- 
arm  without  the  insulator  thimble.  The  insulator  thimble 
shall  be  arranged  with  suitable  grooves  for  cement  and  shall 
be  delivered  to  the  insulator  factory  for  installation  in  the  in- 
sulators as  directed,  at  the  expense  of  the  contractor. 

Telephone-line  pins  shall  be  of  steel  with  a  threaded  lead  top 
similar  to  the  standard  telephone  pin  and  shall  be  bolted  to  the 
telephone  cross-arm. 

The  members  of  the  tower  structure  shall  be  made  to  bolt  to- 
gether throughout  and  every  part  shall  be  arranged  for  ready 
assembly  in  the  field  with  wrenches. 

The  quality  of  the  steel  used  in  the  construction  of  the  towers 
shall  be  in  strict  accordance  with  the  latest  specifications  for 
structural  plate  and  rivet  steel  as  adopted  by  the  Association  of 
American  Steel  Manufacturers. 

The  towers  are  to  be  furnished  complete  with  the  necessary 
footings,  cross-arms,  insulator-pins,  ground-wire  clamp,  steps, 
bolts,  nuts  and  washers  and  all  parts  of  the  structures  shall  be 
thoroughly  galvanized  by  the  hot  process  or  the  sherardizing 
process  after  all  punching,  cutting  and  other  machine  work  is 
completed.  The  galvanizing  shall  be  in  accordance  wit'h  the 
specifications  for  galvanizing  attached  hereto. 

Drawings. — The  contractor  shall  submit  with  his  proposal 
duplicate  drawings  showing  the  tower  and  the  details  thereof. 

Inspection. — Purchaser  shall  be  permitted  to  place  an  in- 
spector in  the  factory  of  the  contractor,  who  shall  be  given 
free  access  and  shall  be  granted  authority  to  reject  any  or  all 
such  towers  or  parts  thereof  which  do  not  come  up  to  the  strict 
requirements  of  these  specifications. 

Shipment. — Towers    are    to    be    shipped    " knocked    down" 


APPENDIX  B  275 

with  similar  members  tied  securely  in  bundles  of  approximately 
100  Ib.  each;  the  members  shall  be  systematically  numbered  or 
lettered  so  as  to  allow  of  their  being  easily  assembled.  All  parts 
that  cannot  be  bundled,  such  as  pins,  bolts,  washers,  etc.,  shall 
be  shipped  in  boxes  or  kegs,  in  unit  packages  for  each  individual 
tower,  and  same  shall  be  marked  with  the  tower  height  for  which 
they  are  intended. 

Quantity. — The  number  of  towers  to  be  furnished  under  these 
specifications  is  380;  it  is  agreed,  however,  that  twenty  additional 
towers  may  be  ordered  at  the  same  price,  but  the  delivery  of 
these  extra  towers,  as  well  as  the  special  towers  hereafter  men- 
tioned, must  be  specified  at  the  time  the  contract  is  signed. 

Special  Towers. — In  addition  to  the  above,  the  contractor  is 
asked  to  submit  proposals  for  twelve  45-ft.,  four  50-ft.  and  four 
60-ft.  towers  to  meet  with  these  same  specifications,  and  also  for 
five  transposition  towers,  arranged  as  per  drawing  2135-S. 

Price. — Proposals  shall  state  the  price  per  tower  in  accordance 

with  the  specifications,  f.o.b ,  together 

with  the  time  required  to  complete  the  contract. 


APPENDIX  C 

SPECIFICATIONS  FOR  PIN  TYPE  INSULATORS — LINE  VOLTAGE 

66,000   VOLTS 

The  insulator  manufacturer  shall  be  required  to  furnish  all 
facilities  and  equipment  for  making  the  tests  and  inspections 
as  specified  here  below  and  shall  allow  at  all  times  free  access 
to  such  facilities  and  equipment  to  the  inspector  or  authorized 
representative  of  the  purchaser  until  the  entire  order  is  accepted 
by  same. 

The  insulator  company  agrees  to  deliver  to  the  inspector 
finished  ware  at  the  rate  of  2000  pieces  a  day  continuously 
for  every  week  day  after  arrival  of  said  inspector  at  the  insulator 
factory  in  response  to  a  written  notification  from  the  insulator 
company  that  the  order  is  ready  for  inspection  and  test. 

GENERAL  SPECIFICATIONS 

The  insulator  shall  be  made  of  first  class  evenly  fired  por- 
celain ware;  each  part,  and  the  insulator  assembled  as  a  whole, 
shall  be  symmetrical  and  not  appreciably  warped. 

Glaze. — The  surface  of  the  ware  shall  be  uniformly  covered 
with  a  medium  thickness  of  smooth  brown  or  slate  colored 
glaze  free  from  grit,  same  to  be  hard  and  firm  and  to  not  become 
dull,  scale  off,  nor  show  any  signs  of  checking  severely  when 
allowed  to  stand  exposed  to  the  elements  for  a  period  of  three 
months  or  subjected  to  a  series  of  six  sudden  temperature 
variations  of  15°  F. 

This  glaze  shall  cover  all  portions  but  top  surface  of  head 
and  inside  of  head,  and  surface  on  intermediates  where  exposed 
to  cement. 

MECHANICAL    INSPECTION 

A  mechanical  inspection  shall  be  made  of  all  insulators  and 
those  shall  be  rejected  which  contain  open  holes  or  cracks  within 

276 


APPENDIX.  C  277 

4  in.  of  the  head,  inside  or  outside,  in  the  case  of  the  top  shell 
or  4  in.  from  the  tops  in  the  case  of  intermediates.  Beyond  this 
range  all  closed  cracks  1/2  in.  in  length  or  over,  if  of  a  weaken- 
ing character  rendering  the  shell  edges  easily  broken  by  a  blow, 
shall  not  be  accepted. 

Air  Cells. — Occasional  samples  of  the  ware^shall  be  broken 
to  see  that  they  do  not  contain  air  cells  or  foreign  matter. 

Fragility. — The  insulator  shall  withstand,  under  the  below 
conditions, 

eight  charges  of  No.  6  shot,  and 

four  charges  of  No.  4  shot  without  breaking. 

The  assembled  insulator  shall  be  rigidly  mounted  upon  its 
pin  40  ft.  above  ground  and  the  man  doing  the  testing  shall 
stand  fifteen  paces  from  the  base  of  the  pole. 

The  testing  shall  be  done  with  a  No.  12  gage  choke-bore 
shot  gun. 

The  charge  shall  consist  of  3  1/4  drams  of  smokeless  powder 
and  1  1/8  oz.  of  shot,  Winchester  Leader  shell  being  preferred. 

Strain  Test. — The  insulator  shall  not  exceed  16  in.  in  height 
over  all  and  when  mounted  upon  its  pin  shall  be  capable  of 
withstanding  without  injury  to  or  a  loosening  of  any  of  the 
parts,  a  stress  of  2000  Ibs.  applied  at  the  tie  groove  from  any 
direction  in  a  plane  at  right  angles  to  the  axis  of  the  insulator. 

The  Cement  used  in  assembling  shall  be  of  the  best  quality 
of  portland,  neatly  run  in  and  thin  enough  to  fill  every  irregular- 
ity, then  allowed  to  firmly  set,  at  least  forty-eight  hours, 
before  being  disturbed. 

ELECTRICAL    TESTS 

One  insulator  of  each  particular  design  shall  be  subjected 
to  the  following  tests  with  insulator  assembled  on  its  metal  pin. 
(By  spark  gap,  American  Institute  of  Electrical  Engineers' 
curve.) 

A  piece  of  the  line  conductor  4  ft.  in  length  shall  be  tied  or 
fastened  to  the  insulator  as  upon  the  line  and  used  for  one 
terminal. 

Dry  Test. — Fifteen  minutes  continuous,  180,000  volts. 

Wet  Test. — Fifteen  minutes,  125,000  volts  continuous.  Spray 
nozzle,  5  ft.  distant;  1/4-in.  precipitation  per  minute  at  45° 
angle  from  insulator  axis. 


278  TRANSMISSION  LINE  CONSTRUCTION 

Puncture  Test. — Each  part  of  the  sample  shall  be  soaked  for 
forty-eight  hours  continuously  in  water,  then  inverted  in 
1/4  in.  of  water  which  shall  form  one  electrode  and  the  part 
shall  act  as  a  receptacle  for  1/4  in.  of  water  which  shall  be  the 
second  electrode,  and  a  voltage  shall  be  applied  continuously 
for  fifteen  minutes  between  these  electrodes,  the  voltage  to  be 
held  just  below  arc-over  point. 

The  entire  order  of  insulators  shall  be  subjected  to  the  follow- 
ing inspection  and  test: 

I. — A  general  mechanical  inspection  of  all  the  parts  in  view 
of  locating  and  rejecting  those  having  objectionable  fissures, 
distortions,  etc. 

The  inspector  should  use  a  light-weight  mallet  to  rap  each 
part  and  note  the  "ring"  which  will  assist  in  showing  up  those 
that  are  defective. 

II. — Electrical  tests  upon  the  entire  lot  of  insulators  shall 
be  as  follows: 

(a)  Puncture   test — as   specified   above  for  sample,  omitting 
the  forty-eight  hour  absorption  test. 

(b)  Dry    test — complete     insulators,  assembled,    are    to    be 
mounted  upon  metal  pins  and  tested  between  the   tie-grooves 
and  pins  with  180,000  volts  alternating  current  continuously 
for  ten  minutes  minimum  and  two  minutes  after  the  last  break- 
down, that  is,   if  a  group   of  the  insulators  are  being  tested 
simultaneously  and  after  nine  minutes  one  insulator  fails,  the 
test  must  be  continued  two  minutes  longer  upon  the  entire  group. 

BOXING 

The  purchaser  will  advise  the  insulator  company  previous 
to  placing  the  contract  whether  the  insulators  shall  be  shipped 
set  "knocked  down"  in  barrels  or  boxes,  or  shipped  set  up  in 
crates  and  will  also  supply  specific  shipping  instructions  or 
means  of  disposal  of  the  ware  within  three  days  after  the  inspec- 
tion begins. 


APPENDIX  D 

SPECIFICATION  FOR  GALVANIZING  FOR  IRON  OR  STEEL 

These  specifications  give  in  detail  the  test  to  be  applied  to 
galvanized  material.  All  specimens  shall  be  capable  of  with- 
standing these  tests. 

A.  Coating. — The   galvanizing  shall  consist  of  a  continuous 
coating  of  pure  zinc  of  uniform  thickness,  and  so  applied  that  it 
adheres  firmly  to  the  surface  of  the  iron  or  steel.     The  finished 
product  shall  be  smooth. 

B.  Cleaning. — The   samples   shall  be  cleaned  before   testing, 
first  with   benzine   or  turpentine,  and  cotton  waste  (not  with 
a  brush) ,  and  then  thoroughly  rinsed  in  clean  water  and  wiped 
dry  with  clean  cotton  waste. 

The  sample  shall  be  clean  and  dry  before  each  immersion  in  the 
solution. 

C.  Solution. — The    standard     solution     of     copper    sulphate 
shall  consist  of  commercial  copper  sulphate  crystals  dissolved  in 
cold   water,   about  in  the   proportion   of  thirty-six  parts,   by 
weight,   of  crystals  to   100  parts,  by  weight,   of  water.    ,The 
solution  shall  be  neutralized  by  the  addition  of  an  excess  of 
chemically  pure  cupric  oxide  (Cu.O).     The  presence  of  an  ex- 
cess of  cupric  oxide  will  be  shown  by  the  sediment  of  this  reagent 
at  the  bottom  of  the  containing  vessel. 

The  neutralized  solution  shall  be  filtered  before  using  by 
passing  through  filter  paper.  The  filtered  solution  shall  have 
a  specific  gravity  of  1.186  at  65°  F.  (reading  the  scale  at  the  level 
of  the  solution)  at  the  beginning  of  each  test.  In  case  the  filtered 
solution  is  high  in  specific  gravity,  clean  water  shall  be  added  to 
reduce  the  specific  gravity  to  1.186  at  65°  F.  In  case  the  filtered 
solution  is  low  in  specific  gravity,  filtered  solution  of  a  higher 
specific  gravity  shall  be  added  to  make  the  specific  gravity 
1.186  at  65°  F. 

As  soon  as  the  stronger  solution  is  taken  from  the  vessel  con- 
taining the  unfiltered  neutralized  stock  solution,  additional 
crystals  and  water  must  be  added  to  the  stock  solution.  An 

279 


280  TRANSMISSION  LINE  CONSTRUCTION 

excess  of  cupric  oxide  shall  always  be  kept  in  the  unfiltered 
stock  solution. 

D.  Quantity  of  Solution. — Wire  samples  shall  be  tested  in  a 
glass  jar  of  at  least  two  (2)  in.  inside  diameter.     The  jar  without 
the  wire  samples  shall  be  filled  with  standard  solution  to   a 
depth  of  at  least  four  (4)  in.     Hardware  samples  shall  be  tested 
in  a  glass  or  earthenware  jar  containing  at  least  one-half  (1/2) 
pint  of  standard  solution  for  each  hardware  sample. 

Solution  shall  not  be  used  for  more  than  one  series  of  four 
immersions. 

E.  Samples. — Not  more  than  seven  wires  shall  be  simultane- 
ously immersed,  and  not  more  than  one  sample  of  galvanized 
material   other  than  wire  shall  be  immersed  in  the  specified 
quantity  of  solution. 

The  samples  shall  not  be  grouped  or  twisted  together,  but 
shall  be  well  separated  so  as  to  permit  the  action  of  the  solution 
to  be  uniform  upon  all  immersed  portions  of  the  samples. 

F.  Test. — Clean  and  dry  samples  shall  be  immersed  in  the 
required  quantity  of  standard  solution  in  accordance  with  the 
following  cycle  of  immersions. 

The  temperature  of  the  solution  shall  be  maintained  be- 
tween 62°  F.  and  68°  F.  at  all  times  during  the  following  test: 

First:        Immerse  for  one  minute,  wash  and  wipe  dry. 

Second:    Immerse  for  one  minute,  wash  and  wipe  dry. 

Third:      Immerse  for  one  minute,  wash  and  wipe  dry. 

Fourth:    Immerse  for  one  minute,  wash  and  wipe  dry. 

After  each  immersion  the  samples  shall  be  immediately 
washed  in  clean  water  having  a  temperature  between  62°  F.  and 
68°  F.,  and  wiped  dry  with  cotton  waste. 

In  the  case  of  No.  14  galvanized  iron  or  steel  wire,  the  time 
of  the  fourth  immersion  shall  be  reduced  to  one-half  minute. 

G.  Rejection. — If   after   the   test   described   in   Section   "~F" 
there   should   be   a   bright   metallic    copper   deposit   upon   the 
samples,  the  lot  represented  by  the  sample  shall  be  rejected. 

Copper  deposits  on  zinc  or  within  one  inch  of  the  cut  end 
shall  not  be  considered  causes  for  rejection. 

"  In  the  case  of  a  failure  of  only  one  wire  in  a  group  of  seven 
wires  immersed  together,  or  if  there  is  a  reasonable  doubt  as  to  the 
copper  deposit,  two  check  tests  shall  be  made  on  these  seven 
wires  and  the  lot  reported  in  accordance  with  the  majority  of 
the  sets  of  tests. 


APPENDIX  E  281 

GENERAL  SPECIFICATIONS  FOR  HIGH-TENSION  LINK  TYPE 
INSULATORS 

1.  General. — The  intentions  of  these  specifications  is  to  pro- 
vide for  all  labor,  tools  and  material  required  to  furnish  and 

deliver,  f.o.b ,  in  complete  and  satisfactory  condition, 

as    provided   for   in   these    specifications,    approximately    five- 
hundred  (500)  complete  high-tension  link  type  suspension  insu- 
lators,  and  approximately  two-hundred   (200)    complete  high- 
tension  link  type  strain  insulators,  as  outlined  below. 

2.  Drawings. — With   his   proposal,   the   bidder   shall   submit 
drawings  showing  the  general  type  and  dimensions  of  the  insu- 
lator   parts    and    of  the   assembled  insulators  he   proposes  to 
furnish. 

After  the  contract  has  been  awarded,  the  contractor  shall 
send  the  company  four  signed  blue  prints  of  drawings  showing 
the  general  design  and  the  details  of  insulator  and  accessories. 
One  print  will  be  checked  and  returned  to  the  contractor  with 
approval  or  criticism  noted,  and  three  prints  will  be  retained  by 
the  company  for  its  files. 

The  contractor  shall  notify  the  company  promptly  of  any 
changes  which  may  be  necessary  in  any  drawing,  print  of  which 
has  been  submitted  to  the  company  for  approval,  and  on  which 
action  is  pending.  After  a  drawing  has  been  approved  by  the 
company,  the  contractor  shall  make  no  changes  until  he  has 
received  the  written  consent  of  the  company. 

The  contractor  shall  be  responsible  for  the  correctness  of  all 
drawings  even  though  they  may  have  been  approved  by  the 
company. 

Besides  the  drawings  mentioned  above,  the  contractor  shall 
furnish  such  additional  drawings  and  information  regarding  the 
general  design,  construction,  connections,  number  and  size  of 
parts  as  may  be  required  by  the  Engineer. 

Any  materials  ordered,  or  work  commenced  before  the  approval 
of  the  drawings,  shall  be  at  the  contractor's  risk. 

3.  General  Requirements. — The  insulators  will  be  used  for  a 
sixty-six  thousand  (66,000)  volt,  delta  connected  three-phase, 
60  cycle  transmission  line  carried  on  steel  towrers.     The  line  will 
be  located  in  a  country  subject  to  severe  lightning  and  wind 
storms  and  will  be  operated  in  connection  with  a  transmission 
system  comprising  about  120  miles  of  line. 


282  TRANSMISSION  LINE  CONSTRUCTION 

The  insulators  are  to  be  furnished  complete  with  all  links, 
clamps,  bolts,  and  other  parts  necessary  to  make  them  complete 
and  ready  to  bolt  to  the  cross-arm  and  to  receive  the  line  wire. 

The  connecting  links  and  insulator  hardware  shall  be  such  de- 
sign as  will  allow  of  the  ready  replacement  of  any  unit  in  the 
string  or  permit  of  the  addition  of  one  or  more  units  to  the  string 
without  requiring  any  change  whatsoever  or  any  variation  from 
the  standard  type  of  unit. 

The  operating  voltage  shall  be  approximately  twenty-five 
thousand  (25,000)  volts  per  porcelain  unit. 

4.  Workmanship  and  Materials. — All  workmanship  and  mate- 
rials shall  be  first-class  and  the  best  of  their  respective  kinds,  and 
must  be  in  full  accord  with  the  best  modern  engineering  practice. 
Only  the  very  best  grade  of  electrical  porcelain  clay  shall  be  used. 
The  fracture  of  the  porcelain  ware  must  not  show  blow-holes, 
cracks,  checks,  or  other  flaws,  and  must  not  show  a  glossy  surface 
as  same  will  be  taken  to  indicate  overfiring. 

The  entire  surface  of  the  ware  excepting  such  areas  as  are 
necessary  for  supporting  the  ware  in  the  kilns,  must  be  uniformly 
coated  with  a  dark  brown  glaze.  The  glaze  must  be  hard, 
smooth,  even,  and  continuous  without  crazing  or  other  flaws. 

The  connecting  links  and  all  hardware  shall  be  thoroughly 
galvanized,  either  by  the  hot  process  or  the  sherardizing  method, 
after  all  punching,  cutting  and  machining  has  been  done.  Bolts 
and  nuts  shall  be  electro-galvanized  or  sherardized  after 
threading.  All  galvanizing  shall  be  first  class  and  in  accordance 
with  the  standard  specifications  appended  hereto. 

5.  General  Design. — The  insulators  shall  consist  of  porcelain 
disks  or  units  strung  in  series  with  connecting  links  of  approved 
design. 

The  disks  or  units  shall  consist  of  one  piece  of  porcelain  and 
shall  not  be  less  than  ten  (10)  inches  in  diameter  and  shall  be 
assembled  on  approximately  six  (6)  inch  centers. 

The  weights  of  the  assembled  insulators  shall  be  approxi- 
mately : 

Suspension  type  .....      units  .  .  Ibs.    net 
Strain units  .  .  Ibs.    net 

6.  Mechanical   Tests. — The  insulators,   completely  assembled 
with  standard  fittings  and  arrangement,  shall  withstand  a  mechan- 
ical test  equivalent  to  a  pull  between  conductor  clamps  and 


APPENDIX  'E  283 

cross-arm  fastening  of  six-thousand  (6000)  pounds.  At  least 
three  insulators  from  each  shipment  shall  be  subjected  to  this 
test. 

7.  Electrical  Test. — Tests  shall  in  all  cases  be  conducted  upon 
the  standard  assembled  insulators,  arranged  as  for  service.     The 
standard  strings  shall  be  placed  under  a  mechanical  load  of  1500 
Ib.  applied  to  them  in  their  normal  operating  position,  and  while 
under  this  strain  they  shall  be  subjected  to  the  following  wet  and 
dry  tests: 

Dry  Test. — The  assembled  insulator  shall  withstand  the  con- 
tinuous application  for  ten  (10)  minutes  of  a  60-cycle  voltage  of 
three  (3)  times  the  rated  line  voltage,  or  198,000  volts,  with  one 
terminal  connected  to  the  suspension  eye  and  the  other  to  the 
conductor  clamp. 

Wet  Test. — The  assembled  insulator  shall  withstand  the  con- 
tinuous application  for  fifteen  (15)  minutes  of  a  60-cycle  voltage 
of  two  (2)  times  the  rated  line  voltage,  or  132,000  volts,  applied 
to  the  suspension  eye  as  one  terminal  and  the  conductor  clamps 
as  the  other,  while  the  insulator  is  subjected  to  a  spray  of  clear 
water  giving  a  precipitation  of  one-fifth  of  an  inch  per  minute, 
with  the  spray  striking  the  insulator  at  an  angle  of  45  degrees 
from  the  vertical. 

For  this  test  the  testing  transformer  shall  be  of  reasonable 
capacity  for  that  class  of  work,  the  wave  form  of  the  voltage 
shall  be  approximately  a  sine  curve,  and  the  voltage  measure- 
ment shall  be  made  with  a  spark  gap  using  No.  3  sharp  needles, 
using  the  standard  spark  gap  curve  of  the  American  Institute 
of  Electrical  Engineers. 

At  least  three  insulators  from  each  shipment  shall  be  subjected 
to  these  tests. 

8.  Inspection. — The  company  shall  have  the  right  to  have  an 
inspector  at  the  place  of  manufacture,  who  will  have  the  authority 
to  reject  any  or  all  such  insulators  or  parts  which  do  not  conform 
to  the  strictest  interpretations  of  these  specifications. 

If  from  any  one  firing,  two  (2)  per  cent,  of  the  porcelain  parts 
show  indications  of  being  overfired,  all  parts  or  units  from  that 
firing  shall  be  rejected. 

The  contractor  shall  allow  the  company's  inspector  free  access 
to  his  factory  during  the  process  of  manufacture  and  testing. 
All  testing  shall  be  done  by  and  at  the  expense  of  the  contractor. 

9.  Packing. — The  contractor  will  state  the  standard  number  of 


284  TRANSMISSION  LINE  CONSTRUCTION 

parts  per  barrel,  crate  or  box,  and  the  method  of  packing.  All 
such  containers  shall  be  plainly  and  correctly  marked  with  the 
number  and  kind  of  parts  therein. 

10.  Final. — It  is  the  intention  of  these  specifications  to  include 
all  labor,  materials,  special  tools  and  parts,  properly  to  construct, 
test  and  deliver  the  apparatus  as  herein  described,  excepting  only 
such  labor  and  materials  as  are  specially  mentioned  as  being 
furnished  by  another  contractor,  and  any  labor,  materials,  fit- 
tings or  apparatus  required  to  properly  complete  the  work  here- 
inbefore described  in  the  spirit  of  these  specifications,  but  not 
especially  mentioned,  shall  be  furnished  by  the  contractor  with- 
out extra  charge. 

It  is  intended  also  that  these  specifications  shall  be  sufficiently 
broad  to  allow  all  manufacturers  of  first-class  insulators,  to 
submit  under  them,  and  any  bidder  who  finds  anything  in  them 
prohibitive  to  the  free  exercise  of  his  best  skill  and  design  in  the 
making  of  insulators  to  fulfill  the  requirements,  may  submit 
propositions  pointing  out  wherein  he  cannot  conform  to  the 
specifications,  and  will  also  submit  complete  detailed  specifica- 
tions of  the  insulators  and  accessories  which  he  proposes  to 
furnish  in  place  of  those  specified  herein. 


APPENDIX  F 

SPECIFICATIONS  FOR  CREOSOTE  OIL 

The  oil  used  shall  be  the  best  obtainable  grade  of  coal-tar 
creosote,  that  is,  it  must  be  a  pure  product  of  coal-tar  distillation 
and  must  be  free  from  admixture  of  oils,  other  tars,  or  sub- 
stances foreign  to  pure  coal-tar.  It  must  be  completely  liquid 
at  38°  C.  and  must  be  free  from  suspended  matter;  the  specific 
gravity  of  the  oil  at  38°  C.  must  be  at  least  1.03. 

When  distilled  according  to  the  common  method,  that  is, 
using  an  8-ounce  retort,  asbestos  covered,  with  a  standard 
thermometer  bulb  one-half  (1/2)  inch  above  the  surface  of  the 
oil,  the  oil  should  show  no  distillation  below  210°  C.,  not  more 
than  25  per  cent,  below  235°  C.  and  the  residue  above  335°  C., 
if  it  exceeds  5  per  cent,  in  quantity  must  be  soft.  The  oil  shall 
not  contain  more  than  3  per  cent,  water. 


285 


INDEX 


PAGE 

Accidents 270 

Accident  report  form : 271 

Aluminum  wire.     (See  Wire,  Aluminum.) 

Anchors  for  guys,  cost  of 223 

dead-man  type 221 

expanding  type 221 

holding  power  of 224 

plate  type 222 

in  rock 22,2 

screw  type 220 

Anchors  for  towers.     (See  Towers,  steel.) 

Angles  in  line,  approach  spans  to 14 

guying  for.     (See  Guying.) 

insulator  arrangement  for 183,  216 

maximum  allowable  on  one  structure 14 

special  towers  for 183 

Arcing  rings  for  insulators 208 

Atlas  sheets 1 

B 

Bi-metallic  wire.     (See  Wire,  Copper-clad.) 

Bolts  for  line  work 186,  187 

Braces,  cross-arm 186,  188 

Braces,  pole,  cost  of  installation 228 

erection  crews 228 

erection  of 215 

laying  out  of 213 

sizes 213 

types 210 

Buck-stayed  corner  poles 212 

Butt  treatment  of  poles.     (See  Poles,  Wooden.) 

C 

Cable.     (See  Wire.) 

Camps  for  construction  crews 268 

Circuit  breaks.     (See  Insulators,  Guy.) 

Clamps,  Clark  insulator 247 

guy..  219 

splicing ...  240 

wire..  217,  240 

Come-a-longs 217,  240 

287 


288  INDEX 

PAGE 

Concrete  bases  for  steel  poles 101 

Concrete  bases  for  steel  towers 110 

Concrete  poles.     (See  Poles,  Concrete.) 
Conductors.     (See  Wire.) 

Connectors  for  sleeve  splicing 240 

Copper  wire.     (See  Wire,  Copper.) 

Core  wire 231 

Cradle  protection  for  R.  R.  crossings 175 

Creosote,  specifications  for Appendix  F 

Creosoting.     (See  Poles,  Wooden  and  Cross-arms) 

Creosoting  machine 69 

Cross-arms,  arrangements  of 26  to  32 

attachment  of 186 

cost  of 185 

cost  of  preservation  of 185 

distribution  of 188 

life  of  wooden 184 

preservation  of 185 

storing  of 188 

timbers  for 184 

Cross-arming,  cost  of 207 

methods  of 205 

D 

Dead-ends,  approach  spans  to '. 14 

insulator  arrangement  for 208 

making  up  wire  at 248 

types  of  special  structures  for  holding 175 

Dead-man  anchors 221 

cost  of 223 

setting  of 221 

Deflection  of  wires.     (See  Sag.) 

Digging  holes,  cost  of 79  to  81 

system 81 

tools  for 81 

Distribution  of  material.      (See  Specific  Material.) 

Duplex  wire.     (See  Wire,  Copper-clad.) 

Dynamometer 243 

E 

Easement,  acquiring  right  of  way  under 20 

contract  form  for  right  of  way  under 21 

cost  of  right  of  way  under 22 

Elastic  line  construction.     (See  Towers,  Steel.) 

Erection  of  concrete  poles.     (See  Poles,  Concrete.) 

Erection  of  steel  poles.     (See  Poles,  Steel.) 

Erection  of  steel  towers.     (See  Towers,  Steel.) 


INDEX  289 

PAGE 


Erection  of  wire.     (See  Wire.) 

Erection  of  wooden  poles.     (See  Poles,  Wooden.) 


Fatigue  of  insulators 194,  195 

G 

Gains 186 

Gaini  ng  poles '. 78 

Galvanizing 107,  App.  D 

Gin-poles 76,  99,  123,  124 

Gin-wagons,  types 83 

cost  of 84 

Glass  insulators 193 

Glaze  on  insulators 194 

Grading  of  line 16 

Graphic  line  foreman's  report 265 

Gravity  disconnecting  appliance  for  R.  R.  crossings 176 

Ground  taps 250 

Ground  wire,  arrangement  of.     (See  particular  type  of  structure.) 

clamps  for 249 

material  for 233 

Grounding ; *  . .  250 

Guying,  anchors  for 219 

clamps  for , 219 

cost  of .  .  f 227,  228 

crews  for 228 

installation  of 217 

insulators  used  in.     (See  Insulators,  Guy.) 

methods  of 211 

storm 212 

wire  for 217 

H 

Hard-drawn  wire.     (See  Wire,  Copper.) 
Hardware.     (See  particular  item.) 

Housing  of  crews 267 

Highways,  right  of  way  along 20 

Highways,  use  of  for  line 34 

I 

Instructons  to  foremen 23 

Insulators,  line,  characteristics  of  materials  for 193 

costs  of 204 

costs  of  distribution 205 

costs  of  installation 207 

distribution  of 205 

glass  for 193 

19 


290  INDEX 

PAGE 

Insulators,  line,  installation  of 207 

molded  composition . 193 

pin  type  versus  suspension  type 194,  198 

points  to  be  specified  in  buying 195 

porcelain  for 193 

protection  of  from  arcs 208 

safety  factor  of 195,  199 

selection  of 194 

shipment  of . ' 204 

specification  for  pin  type App.  C. 

specifications  for  suspension  type App.  E 

storing  of • 205 

tests  of '.  .  .  ,    195,  199 

typical  designs,  pin  type 195 

typical  designs,  suspension  type 200 

typical  designs,  European 195,  202 

Insulators,  guy,  cost  of  porcelain 226 

cost  of  wooden 226 

porcelain 225 

use  of 224 

wooden 224 

Iron  and  steel  wire.     (See  Wire,  Iron  and  Steel.) 

J 

Joints  in  wire,  cable  or  sun-burst 240 

sleeve 240 

Western  Union 241 

Junction  towers 173 

K 

Knife  disconnecting  switches.     (See  Switches.) 

L 

Load  assumptions  in  design  of  structures 105 

Load  assumptions  in  computing  sag 242 

Location  of  line.     (See  also  Surveys.) 

along  roads 3 

along  section  lines 4 

as  affected  by  lightning  conditions 4 

general  conditions  to  be  satisfied  in 5 

Log  of  construction  work 265 

M 

Maps,  detail 15 

general 1 

topographic 1 

Material  estimates IS 

Material  records.  .                                                                                               .  266 


INDEX  291 

O 

PAGE 

Open  tank  butt  treatments;  cost  of 65,  66 

methods 61 

theory  of 61 

typical  plants  for 62 

Organization  of  crews  for  work 262 


Paraffine,  treating  pins  with 189 

Pins;,  composite 193 

Pins,  steel,  types 189 

use  of .    188,  193 

Pins,  wooden,  preservation  of 189 

specifications  for 189 

timber  for 188,  189 

use  of 188,  193 

Poles,  concrete,  cost  of 151 

cost  of  distributing 152 

cost  of  erecting 153 

costs  of  lines  using 261 

distribution  of 152 

factor  of  safety  in  design  of 150 

forms  for  molding  of 135 

life  of 8,  153 

machine  molding  of 141 

reinforcement  of 136 

reliability  of 9 

strength  of  typical 147 

tests  of 147 

types  of 52 

weights  of 150 

Poles,  steel,  car-loading  of 98 

concrete  bases  for 100,  101 

cost  of 98 

cost  of  distributing 99 

cost  of  erecting 102 

cost  of  lines  using 102,  260 

cost  of  unloading 99 

depth  of  set  of 100 

diamond  type • .  .  .      39 

distribution  of 99 

erection  of 100 

erection  crews  for 101,  102 

latticed  type 35,  90 

life  of 8 

spans  for  lines  of 89 

Tripartite  type 40 

types  of 35  to  43 


292  INDEX 

PAGE 

unloading  cars  of 98 

use  of 89,  102 

weights  of 90,  94 

Poles,  wooden,  A  and  H  frame  structures  of 34 

car-loading  of 73,  74 

cost  of 73 

cost  of  digging  holes  for 79 

cost  of  distributing 77 

cost  of  erecting  with  pikes 82 

cost  of  erecting  with  gin-wagon 84 

cost  of  framing  of 78 

cost  of  preservative  treatment  of 60,  65,  66 

cost  of  treated 69 

cost  of  unloading 75 

cost  of  typical  lines  using 253 

cutting  of 56 

decay  of ' 57,  58 

depth  of  set  of 79 

digging  holes  for 79  to  81 

distribution  of ' 77 

framing  of 78 

life  of  treated 66,  70 

life  of  untreated 8,  55,  57 

loading  for  distribution 76 

long  span  construction  with 32 

preservative  treatment  of 59  to  71 

raising  and  setting  with  pikes 82 

raising  and  setting  with  gin-wagon 83 

seasoning  of 56 

spans  employed  with 26,  71 

special  structures  of 87 

specifications  for  white  cedar App.  A 

standard  dimensions  of 72 

storage  of 56,  75,  76 

timbers  used  for 55 

typical  cross-arm  arrangements  for 26  to  32 

unloading  of 74 

usual  sizes  and  lengths  employed 25,  71 

weights  of 74 

Porcelain,  quality  for  insulators 194 

Preliminary  investigations  for  a  line 3 

Profiles 16 

Progress  report .  .    265 

Pulling  up  wire.     (See  Wire.) 

R 

Railroad  crossings. 175,  179,  181 

Reels..  .   234 


INDEX  293 

PAGE 

Reel  wagons 236 

Report  forms  for  construction  work 263,  265 

Right  of  way,  contract  form  for 21 

cost  of 22 

methods  of  acquiring 20 

River  crossings 162 

Rock,  anchors  in 222 

Rock,  pole  holes  in 81 

Route  of  line,  final,  determination  of 7 

map  of 15 

survey  of 11 

Route  of  line,  preliminary,  investigation  of 3 

points  to  be  considered  in  laying  out 2 

S 

Sag,  computation  of 243 

curve  for  construction  foreman 243 

determining  with  dynamometer 243 

determining  on  profile 16 

maximum  load  assumed  in  computing 242 

sighting  for 243 

Sectionalizing  switches.     (See  Switches.) 

Shear  legs 124 

Shear  pole 124 

Shipments,  checking  of 265 

routing  of 19 

schedule  of 19 

Spans,  concrete  pole  construction 89 

steel  pole  construction 89 

steel  tower  construction 107 

.    wooden  pole  construction 26,  32,  71 

Splices.     (Also  see  Joints.) 

cost  of 242 

strength  of 241 

types  of 240 

Staking  out.     (See  Surveys.) 

Steel  wire.     (See  Wire,  Iron  and  Steel.) 

Strain  insulators.     (See  Insulators.) 

Stringing  wire.     (See  Wire.) 

Surveys,  cost  of 5 

equipment  for 5,  1 1 

instructions  to  party  making 6,  13 

location 11 

methods  of  carrying  on 11 

preliminary 5 

Switches,  Baum 167 

Burke '. .  167 

cost  of  out-door  line .173 


294  INDEX 

PAGE 

Switches,  Kilarc 168 

knife  disconnecting 166 

Switch  structures 164 

T 

Tamping 87 

Teams,  handling  of  in  work 269 

Telephone  and  telegraph  line  crossings 180,  181 

Templets  for  setting  anchors Ill,  112 

Time-keeping ' 264 

Tools  and  tool-keeping 267 

Towers,  steel,  anchor  settings  for 110 

assembling  of 108,  117 

bracing  against  erection  strains 129 

conductor  arrangements  on 47  to  52 

cost  of 107 

cost  of  assembling 120 

cost  of  distributing 110 

cost  of  raising 133 

cost  of  right  of  way  for 22 

cost  of  setting  anchors 116 

cost  of  typical  lines  using 255-260 

distribution  of 109 

erection  crew  for  work  on 131 

erection  tools  and  equipment  for  work  on 131 

flexible  and  rigid  systems 45,  103 

heights  generally  used 107 

life  of '. 8 

maximum  load  assumptions  in  design  of 106 

protection  from  corrosion 107 

raising  of 123,  132 

safety  factors  employed  in  design  of 106 

setting  anchors  of 112 

size  of  members  of 108 

shipments  of 108 

spans  employed  with 107 

specifications  for  typical App.  B 

staking  out  locations  for 13,15,  111 

typical  designs  of .    47  to  52 

unloading  and  storing  of 108 

use  of 103 

weights  of 107 

Transmission  line  crossings 182 

Transposition  structures 156 

Trees,  right  of  way  through 4 

Trunnions  for  tower  erection 127 

Tying-in  line  wires , 244 


INDQX  295 

W 

PAGE 

Wind  pressures  on  spans  and  structures 106,  242 

Wire,  checking  shipments 234 

clamps  for  use  with  pin-type  insulators 247 

clamps  for  use  with  suspension  insulators 249 

cost  of  distribution 235 

cost  of  erection  per  mile 251 

crews  for  erection  of 251 

distribution  of 235 

equalizer  rig  for  pulling-up 

erection  of 237 

grips  for 240 

lengths  on  reels .' .    •  234 

pulling-up .  238 

reels  for -  234 

reel  wagons  for .  236 

running  out  wire 236 

sag  in.     (See  Sag.) 

splices  in 240 

tying-in 244 

types  of  ties 244 

unloading  and  storing 234 

Wire,  aluminum,  characteristics 231 

stringing  of.     (See  Wire,  erection  of) 

ties  for 247 

Wire,  copper,  characteristics ' 230 

stranding  of 231 

stringing  of.     (See  Wire,  erection  of) 

ties  for 247 

Wire,  copper  clad,  characteristics 232 

uses  of 232,  233 

Wire,  iron  and  steel,  characteristics 234 

uses  of 233 

Wooden  guy  insulators 224 


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